* can't use ramdisk as cache device. Receive "Can't attach [UUID]: cache set not found" error @ 2016-02-16 2:40 Scott McGillivray 2016-02-24 7:37 ` Eric Wheeler 0 siblings, 1 reply; 9+ messages in thread From: Scott McGillivray @ 2016-02-16 2:40 UTC (permalink / raw) To: linux-bcache Hello I am using Ubuntu 15.10 with latest nightly 4.5 kernel. Ubuntu creates 16 RAM drives as /dev/ram0 - ram16 by default and i am trying to test bcache and use one of these as a cache device. wipefs /dev/sdd wipefs /dev/sdd -a wipefs /dev/ram0 wipefs /dev/ram0 -a make-bcache -B /dev/sdd -C /dev/ram0 At this point there were no errors output but there is also no UUID entry in /sys/fs/bcache/. Only register and register_quiet. bache-super-show correctly prints info about both block and cache devices when queried but when i try to manually attach the cache device with echo cset.uuid > /sys/block/bcache0/bcache/attach i get no error but in dmesg i see bcache: __cached_dev_store() Can't attach 3f2521a6-2103-4e2e-a47d-cc56558e8f7d: cache set not found If i repeat this example but use another sd block device as cache then it works OK. Can anyone confirm if it should be possible to use the ramdisk based block device as a caching device with bcache ? I also tried to use a loop device as cache and that didn't work either.. i got "kernel bug" in dmesg for drivers/md/bcache/super.c:1812. RIP [] cache_alloc.isra.21+0x646/0x670[bcache] Does bcache need the cache device to be a certain block type i.e sd 8 ? Should i be able to use any block device from /proc/devices as a cache device ? The kernel options used for ramdisk are: CONFIG_BLK_DEV_RAM=y CONFIG_BLK_DEV_RAM_COUNT=16 CONFIG_BLK_DEV_RAM_SIZE=65536 CONFIG_BLK_DEV_RAM_DAX=y Thank you. Scott ^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: can't use ramdisk as cache device. Receive "Can't attach [UUID]: cache set not found" error 2016-02-16 2:40 can't use ramdisk as cache device. Receive "Can't attach [UUID]: cache set not found" error Scott McGillivray @ 2016-02-24 7:37 ` Eric Wheeler 2016-02-25 5:55 ` Scott McGillivray 0 siblings, 1 reply; 9+ messages in thread From: Eric Wheeler @ 2016-02-24 7:37 UTC (permalink / raw) To: Scott McGillivray; +Cc: linux-bcache On Tue, 16 Feb 2016, Scott McGillivray wrote: > Hello > > I am using Ubuntu 15.10 with latest nightly 4.5 kernel. Ubuntu creates > 16 RAM drives as /dev/ram0 - ram16 by default and i am trying to test > bcache and use one of these as a cache device. > > wipefs /dev/sdd > wipefs /dev/sdd -a > wipefs /dev/ram0 > wipefs /dev/ram0 -a > make-bcache -B /dev/sdd -C /dev/ram0 Does it work with /dev/zram0? You would prep it something like this: modprobe zram echo $((1024*1024*1024)) > /sys/block/zram0/disksize # 1GB make-bcache -C /dev/zram0 -Eric > At this point there were no errors output but there is also no UUID > entry in /sys/fs/bcache/. Only register and register_quiet. > > bache-super-show correctly prints info about both block and cache > devices when queried but when i try to manually attach the cache > device with echo cset.uuid > /sys/block/bcache0/bcache/attach i get no > error but in dmesg i see > > bcache: __cached_dev_store() Can't attach > 3f2521a6-2103-4e2e-a47d-cc56558e8f7d: cache set not found > > If i repeat this example but use another sd block device as cache then > it works OK. > > Can anyone confirm if it should be possible to use the ramdisk based > block device as a caching device with bcache ? > > I also tried to use a loop device as cache and that didn't work > either.. i got "kernel bug" in dmesg for > drivers/md/bcache/super.c:1812. RIP [] > cache_alloc.isra.21+0x646/0x670[bcache] > > Does bcache need the cache device to be a certain block type i.e sd 8 > ? Should i be able to use any block device from /proc/devices as a > cache device ? > > The kernel options used for ramdisk are: > > CONFIG_BLK_DEV_RAM=y > CONFIG_BLK_DEV_RAM_COUNT=16 > CONFIG_BLK_DEV_RAM_SIZE=65536 > CONFIG_BLK_DEV_RAM_DAX=y > > Thank you. > Scott > -- > To unsubscribe from this list: send the line "unsubscribe linux-bcache" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- Eric Wheeler, President eWheeler, Inc. dba Global Linux Security 888-LINUX26 (888-546-8926) Fax: 503-716-3878 PO Box 25107 www.GlobalLinuxSecurity.pro Linux since 1996! Portland, OR 97298 ^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: can't use ramdisk as cache device. Receive "Can't attach [UUID]: cache set not found" error 2016-02-24 7:37 ` Eric Wheeler @ 2016-02-25 5:55 ` Scott McGillivray 2016-02-25 6:44 ` Eric Wheeler 0 siblings, 1 reply; 9+ messages in thread From: Scott McGillivray @ 2016-02-25 5:55 UTC (permalink / raw) To: Eric Wheeler; +Cc: linux-bcache No, doesn't' work either i'm afraid. Below is example of failing silently with ram disk and succeeded with HDD as cache device. Tested with /lib/modules/4.5.0-rc3+/kernel/drivers/md/bcache/bcache.ko with zram - doesn't work ================= $ ls -al /sys/fs/bcache/ total 0 drwxr-xr-x 2 root root 0 Feb 25 13:42 . drwxr-xr-x 9 root root 0 Feb 25 13:40 .. --w------- 1 root root 4096 Feb 25 13:40 register --w------- 1 root root 4096 Feb 25 13:40 register_quiet $ file /dev/zram0 /dev/zram0: block special (250/0) $ fdisk -l /dev/zram0 Disk /dev/zram0: 1 GiB, 1073741824 bytes, 262144 sectors $ make-bcache -C /dev/zram0 UUID: 87e63981-7bd8-4cc3-93db-9ca275367c21 Set UUID: 0bba8852-ad4f-41f4-bfa3-679a886a14ad version: 0 nbuckets: 2048 block_size: 8 bucket_size: 1024 nr_in_set: 1 nr_this_dev: 0 first_bucket: 1 No errors, but nothing in dmesg and contents of /sys/fs/bcache/ remain exactly the same... no UUID. Seems to just silently fail. with HDD - works as expected. ===================== $ fdisk -l /dev/sdf Disk /dev/sdf: 1 GiB, 1073741824 bytes, 2097152 sectors $ file /dev/sdf /dev/sdf: block special (8/80) $ make-bcache -C /dev/sdf UUID: 3234c9e7-8186-4a7c-99a8-ae6a371c6f2c Set UUID: 9a71faf7-a408-4f4d-906e-e5d67e43291f version: 0 nbuckets: 2048 block_size: 1 bucket_size: 1024 nr_in_set: 1 nr_this_dev: 0 first_bucket: 1 $ ls -al /sys/fs/bcache/ total 0 drwxr-xr-x 3 root root 0 Feb 25 13:48 . drwxr-xr-x 9 root root 0 Feb 25 13:40 .. drwxr-xr-x 7 root root 0 Feb 25 13:48 9a71faf7-a408-4f4d-906e-e5d67e43291f --w------- 1 root root 4096 Feb 25 13:40 register --w------- 1 root root 4096 Feb 25 13:40 register_quiet $ dmesg [ 714.168488] bcache: register_cache() registered cache device sdf Thank you. On 24 February 2016 at 15:37, Eric Wheeler <lists@ewheeler.net> wrote: > > On Tue, 16 Feb 2016, Scott McGillivray wrote: > >> Hello >> >> I am using Ubuntu 15.10 with latest nightly 4.5 kernel. Ubuntu creates >> 16 RAM drives as /dev/ram0 - ram16 by default and i am trying to test >> bcache and use one of these as a cache device. >> >> wipefs /dev/sdd >> wipefs /dev/sdd -a >> wipefs /dev/ram0 >> wipefs /dev/ram0 -a >> make-bcache -B /dev/sdd -C /dev/ram0 > > Does it work with /dev/zram0? You would prep it something like this: > > modprobe zram > echo $((1024*1024*1024)) > /sys/block/zram0/disksize # 1GB > make-bcache -C /dev/zram0 > > -Eric > > > >> At this point there were no errors output but there is also no UUID >> entry in /sys/fs/bcache/. Only register and register_quiet. >> >> bache-super-show correctly prints info about both block and cache >> devices when queried but when i try to manually attach the cache >> device with echo cset.uuid > /sys/block/bcache0/bcache/attach i get no >> error but in dmesg i see >> >> bcache: __cached_dev_store() Can't attach >> 3f2521a6-2103-4e2e-a47d-cc56558e8f7d: cache set not found >> >> If i repeat this example but use another sd block device as cache then >> it works OK. >> >> Can anyone confirm if it should be possible to use the ramdisk based >> block device as a caching device with bcache ? >> >> I also tried to use a loop device as cache and that didn't work >> either.. i got "kernel bug" in dmesg for >> drivers/md/bcache/super.c:1812. RIP [] >> cache_alloc.isra.21+0x646/0x670[bcache] >> >> Does bcache need the cache device to be a certain block type i.e sd 8 >> ? Should i be able to use any block device from /proc/devices as a >> cache device ? >> >> The kernel options used for ramdisk are: >> >> CONFIG_BLK_DEV_RAM=y >> CONFIG_BLK_DEV_RAM_COUNT=16 >> CONFIG_BLK_DEV_RAM_SIZE=65536 >> CONFIG_BLK_DEV_RAM_DAX=y >> >> Thank you. >> Scott >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-bcache" in >> the body of a message to majordomo@vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html >> > > > > -- > Eric Wheeler, President eWheeler, Inc. dba Global Linux Security > 888-LINUX26 (888-546-8926) Fax: 503-716-3878 PO Box 25107 > www.GlobalLinuxSecurity.pro Linux since 1996! Portland, OR 97298 > ^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: can't use ramdisk as cache device. Receive "Can't attach [UUID]: cache set not found" error 2016-02-25 5:55 ` Scott McGillivray @ 2016-02-25 6:44 ` Eric Wheeler 2016-02-25 7:06 ` Scott McGillivray 0 siblings, 1 reply; 9+ messages in thread From: Eric Wheeler @ 2016-02-25 6:44 UTC (permalink / raw) To: Scott McGillivray; +Cc: linux-bcache On Thu, 25 Feb 2016, Scott McGillivray wrote: > No, doesn't' work either i'm afraid. Below is example of failing > silently with ram disk and succeeded with HDD as cache device. > > Tested with /lib/modules/4.5.0-rc3+/kernel/drivers/md/bcache/bcache.ko > > > with zram - doesn't work > ================= > > $ ls -al /sys/fs/bcache/ > total 0 > drwxr-xr-x 2 root root 0 Feb 25 13:42 . > drwxr-xr-x 9 root root 0 Feb 25 13:40 .. > --w------- 1 root root 4096 Feb 25 13:40 register > --w------- 1 root root 4096 Feb 25 13:40 register_quiet > > $ file /dev/zram0 > /dev/zram0: block special (250/0) > > $ fdisk -l /dev/zram0 > Disk /dev/zram0: 1 GiB, 1073741824 bytes, 262144 sectors > > $ make-bcache -C /dev/zram0 > UUID: 87e63981-7bd8-4cc3-93db-9ca275367c21 > Set UUID: 0bba8852-ad4f-41f4-bfa3-679a886a14ad > version: 0 > nbuckets: 2048 > block_size: 8 > bucket_size: 1024 > nr_in_set: 1 > nr_this_dev: 0 > first_bucket: 1 did you `echo /dev/zram0 > /sys/fs/bcache/register` and then `echo <CSET-UUID> > /sys/block/bcache0/bcache/attach` Not sure which UUID is the CSET UUID. Probably 0bba8852-ad4f-41f4-bfa3-679a886a14ad. See attaching bcache0 to a cache: https://www.kernel.org/doc/Documentation/bcache.txt -Eric > > > No errors, but nothing in dmesg and contents of /sys/fs/bcache/ remain > exactly the same... no UUID. Seems to just silently fail. > > > with HDD - works as expected. > ===================== > > $ fdisk -l /dev/sdf > Disk /dev/sdf: 1 GiB, 1073741824 bytes, 2097152 sectors > > $ file /dev/sdf > /dev/sdf: block special (8/80) > > $ make-bcache -C /dev/sdf > UUID: 3234c9e7-8186-4a7c-99a8-ae6a371c6f2c > Set UUID: 9a71faf7-a408-4f4d-906e-e5d67e43291f > version: 0 > nbuckets: 2048 > block_size: 1 > bucket_size: 1024 > nr_in_set: 1 > nr_this_dev: 0 > first_bucket: 1 > > $ ls -al /sys/fs/bcache/ > total 0 > drwxr-xr-x 3 root root 0 Feb 25 13:48 . > drwxr-xr-x 9 root root 0 Feb 25 13:40 .. > drwxr-xr-x 7 root root 0 Feb 25 13:48 9a71faf7-a408-4f4d-906e-e5d67e43291f > --w------- 1 root root 4096 Feb 25 13:40 register > --w------- 1 root root 4096 Feb 25 13:40 register_quiet > > $ dmesg > [ 714.168488] bcache: register_cache() registered cache device sdf > > > Thank you. > > On 24 February 2016 at 15:37, Eric Wheeler <lists@ewheeler.net> wrote: > > > > On Tue, 16 Feb 2016, Scott McGillivray wrote: > > > >> Hello > >> > >> I am using Ubuntu 15.10 with latest nightly 4.5 kernel. Ubuntu creates > >> 16 RAM drives as /dev/ram0 - ram16 by default and i am trying to test > >> bcache and use one of these as a cache device. > >> > >> wipefs /dev/sdd > >> wipefs /dev/sdd -a > >> wipefs /dev/ram0 > >> wipefs /dev/ram0 -a > >> make-bcache -B /dev/sdd -C /dev/ram0 > > > > Does it work with /dev/zram0? You would prep it something like this: > > > > modprobe zram > > echo $((1024*1024*1024)) > /sys/block/zram0/disksize # 1GB > > make-bcache -C /dev/zram0 > > > > -Eric > > > > > > > >> At this point there were no errors output but there is also no UUID > >> entry in /sys/fs/bcache/. Only register and register_quiet. > >> > >> bache-super-show correctly prints info about both block and cache > >> devices when queried but when i try to manually attach the cache > >> device with echo cset.uuid > /sys/block/bcache0/bcache/attach i get no > >> error but in dmesg i see > >> > >> bcache: __cached_dev_store() Can't attach > >> 3f2521a6-2103-4e2e-a47d-cc56558e8f7d: cache set not found > >> > >> If i repeat this example but use another sd block device as cache then > >> it works OK. > >> > >> Can anyone confirm if it should be possible to use the ramdisk based > >> block device as a caching device with bcache ? > >> > >> I also tried to use a loop device as cache and that didn't work > >> either.. i got "kernel bug" in dmesg for > >> drivers/md/bcache/super.c:1812. RIP [] > >> cache_alloc.isra.21+0x646/0x670[bcache] > >> > >> Does bcache need the cache device to be a certain block type i.e sd 8 > >> ? Should i be able to use any block device from /proc/devices as a > >> cache device ? > >> > >> The kernel options used for ramdisk are: > >> > >> CONFIG_BLK_DEV_RAM=y > >> CONFIG_BLK_DEV_RAM_COUNT=16 > >> CONFIG_BLK_DEV_RAM_SIZE=65536 > >> CONFIG_BLK_DEV_RAM_DAX=y > >> > >> Thank you. > >> Scott > >> -- > >> To unsubscribe from this list: send the line "unsubscribe linux-bcache" in > >> the body of a message to majordomo@vger.kernel.org > >> More majordomo info at http://vger.kernel.org/majordomo-info.html > >> > > > > > > > > -- > > Eric Wheeler, President eWheeler, Inc. dba Global Linux Security > > 888-LINUX26 (888-546-8926) Fax: 503-716-3878 PO Box 25107 > > www.GlobalLinuxSecurity.pro Linux since 1996! Portland, OR 97298 > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-bcache" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > ^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: can't use ramdisk as cache device. Receive "Can't attach [UUID]: cache set not found" error 2016-02-25 6:44 ` Eric Wheeler @ 2016-02-25 7:06 ` Scott McGillivray 2016-02-25 7:26 ` Eric Wheeler 0 siblings, 1 reply; 9+ messages in thread From: Scott McGillivray @ 2016-02-25 7:06 UTC (permalink / raw) To: Eric Wheeler; +Cc: linux-bcache that doesn't work either. It gives the same error from my opening post. Although this time it's also giving a new message in dmesg about block size. bcache: bch_cached_dev_attach() Couldn't attach sdf: block size less than set's block size bcache: __cached_dev_store() Can't attach 0bba8852-ad4f-41f4-bfa3-679a886a14ad : cache set not found which is strange because both devices block size are the same $ blockdev --getbsz /dev/sdf 4096 $ blockdev --getbsz /dev/zram0 4096 On 25 February 2016 at 14:44, Eric Wheeler <bcache@lists.ewheeler.net> wrote: > On Thu, 25 Feb 2016, Scott McGillivray wrote: > >> No, doesn't' work either i'm afraid. Below is example of failing >> silently with ram disk and succeeded with HDD as cache device. >> >> Tested with /lib/modules/4.5.0-rc3+/kernel/drivers/md/bcache/bcache.ko >> >> >> with zram - doesn't work >> ================= >> >> $ ls -al /sys/fs/bcache/ >> total 0 >> drwxr-xr-x 2 root root 0 Feb 25 13:42 . >> drwxr-xr-x 9 root root 0 Feb 25 13:40 .. >> --w------- 1 root root 4096 Feb 25 13:40 register >> --w------- 1 root root 4096 Feb 25 13:40 register_quiet >> >> $ file /dev/zram0 >> /dev/zram0: block special (250/0) >> >> $ fdisk -l /dev/zram0 >> Disk /dev/zram0: 1 GiB, 1073741824 bytes, 262144 sectors >> >> $ make-bcache -C /dev/zram0 >> UUID: 87e63981-7bd8-4cc3-93db-9ca275367c21 >> Set UUID: 0bba8852-ad4f-41f4-bfa3-679a886a14ad >> version: 0 >> nbuckets: 2048 >> block_size: 8 >> bucket_size: 1024 >> nr_in_set: 1 >> nr_this_dev: 0 >> first_bucket: 1 > > did you `echo /dev/zram0 > /sys/fs/bcache/register` > and then `echo <CSET-UUID> > /sys/block/bcache0/bcache/attach` > > Not sure which UUID is the CSET UUID. Probably > 0bba8852-ad4f-41f4-bfa3-679a886a14ad. > > See attaching bcache0 to a cache: > https://www.kernel.org/doc/Documentation/bcache.txt > > -Eric > >> >> >> No errors, but nothing in dmesg and contents of /sys/fs/bcache/ remain >> exactly the same... no UUID. Seems to just silently fail. >> >> >> with HDD - works as expected. >> ===================== >> >> $ fdisk -l /dev/sdf >> Disk /dev/sdf: 1 GiB, 1073741824 bytes, 2097152 sectors >> >> $ file /dev/sdf >> /dev/sdf: block special (8/80) >> >> $ make-bcache -C /dev/sdf >> UUID: 3234c9e7-8186-4a7c-99a8-ae6a371c6f2c >> Set UUID: 9a71faf7-a408-4f4d-906e-e5d67e43291f >> version: 0 >> nbuckets: 2048 >> block_size: 1 >> bucket_size: 1024 >> nr_in_set: 1 >> nr_this_dev: 0 >> first_bucket: 1 >> >> $ ls -al /sys/fs/bcache/ >> total 0 >> drwxr-xr-x 3 root root 0 Feb 25 13:48 . >> drwxr-xr-x 9 root root 0 Feb 25 13:40 .. >> drwxr-xr-x 7 root root 0 Feb 25 13:48 9a71faf7-a408-4f4d-906e-e5d67e43291f >> --w------- 1 root root 4096 Feb 25 13:40 register >> --w------- 1 root root 4096 Feb 25 13:40 register_quiet >> >> $ dmesg >> [ 714.168488] bcache: register_cache() registered cache device sdf >> >> >> Thank you. >> >> On 24 February 2016 at 15:37, Eric Wheeler <lists@ewheeler.net> wrote: >> > >> > On Tue, 16 Feb 2016, Scott McGillivray wrote: >> > >> >> Hello >> >> >> >> I am using Ubuntu 15.10 with latest nightly 4.5 kernel. Ubuntu creates >> >> 16 RAM drives as /dev/ram0 - ram16 by default and i am trying to test >> >> bcache and use one of these as a cache device. >> >> >> >> wipefs /dev/sdd >> >> wipefs /dev/sdd -a >> >> wipefs /dev/ram0 >> >> wipefs /dev/ram0 -a >> >> make-bcache -B /dev/sdd -C /dev/ram0 >> > >> > Does it work with /dev/zram0? You would prep it something like this: >> > >> > modprobe zram >> > echo $((1024*1024*1024)) > /sys/block/zram0/disksize # 1GB >> > make-bcache -C /dev/zram0 >> > >> > -Eric >> > >> > >> > >> >> At this point there were no errors output but there is also no UUID >> >> entry in /sys/fs/bcache/. Only register and register_quiet. >> >> >> >> bache-super-show correctly prints info about both block and cache >> >> devices when queried but when i try to manually attach the cache >> >> device with echo cset.uuid > /sys/block/bcache0/bcache/attach i get no >> >> error but in dmesg i see >> >> >> >> bcache: __cached_dev_store() Can't attach >> >> 3f2521a6-2103-4e2e-a47d-cc56558e8f7d: cache set not found >> >> >> >> If i repeat this example but use another sd block device as cache then >> >> it works OK. >> >> >> >> Can anyone confirm if it should be possible to use the ramdisk based >> >> block device as a caching device with bcache ? >> >> >> >> I also tried to use a loop device as cache and that didn't work >> >> either.. i got "kernel bug" in dmesg for >> >> drivers/md/bcache/super.c:1812. RIP [] >> >> cache_alloc.isra.21+0x646/0x670[bcache] >> >> >> >> Does bcache need the cache device to be a certain block type i.e sd 8 >> >> ? Should i be able to use any block device from /proc/devices as a >> >> cache device ? >> >> >> >> The kernel options used for ramdisk are: >> >> >> >> CONFIG_BLK_DEV_RAM=y >> >> CONFIG_BLK_DEV_RAM_COUNT=16 >> >> CONFIG_BLK_DEV_RAM_SIZE=65536 >> >> CONFIG_BLK_DEV_RAM_DAX=y >> >> >> >> Thank you. >> >> Scott >> >> -- >> >> To unsubscribe from this list: send the line "unsubscribe linux-bcache" in >> >> the body of a message to majordomo@vger.kernel.org >> >> More majordomo info at http://vger.kernel.org/majordomo-info.html >> >> >> > >> > >> > >> > -- >> > Eric Wheeler, President eWheeler, Inc. dba Global Linux Security >> > 888-LINUX26 (888-546-8926) Fax: 503-716-3878 PO Box 25107 >> > www.GlobalLinuxSecurity.pro Linux since 1996! Portland, OR 97298 >> > >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-bcache" in >> the body of a message to majordomo@vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html >> ^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: can't use ramdisk as cache device. Receive "Can't attach [UUID]: cache set not found" error 2016-02-25 7:06 ` Scott McGillivray @ 2016-02-25 7:26 ` Eric Wheeler 2016-02-25 7:39 ` Eric Wheeler 0 siblings, 1 reply; 9+ messages in thread From: Eric Wheeler @ 2016-02-25 7:26 UTC (permalink / raw) To: Scott McGillivray; +Cc: linux-bcache On Thu, 25 Feb 2016, Scott McGillivray wrote: > that doesn't work either. It gives the same error from my opening > post. Although this time it's also giving a new message in dmesg about > block size. > > > bcache: bch_cached_dev_attach() Couldn't attach sdf: block size less > than set's block size > bcache: __cached_dev_store() Can't attach 0bba8852-ad4f-41f4-bfa3-679a886a14ad > : cache set not found > > which is strange because both devices block size are the same > > $ blockdev --getbsz /dev/sdf > 4096 > > $ blockdev --getbsz /dev/zram0 > 4096 Try this: make-bcache -w 4096 -C /dev/zram0 > > > On 25 February 2016 at 14:44, Eric Wheeler <bcache@lists.ewheeler.net> wrote: > > On Thu, 25 Feb 2016, Scott McGillivray wrote: > > > >> No, doesn't' work either i'm afraid. Below is example of failing > >> silently with ram disk and succeeded with HDD as cache device. > >> > >> Tested with /lib/modules/4.5.0-rc3+/kernel/drivers/md/bcache/bcache.ko > >> > >> > >> with zram - doesn't work > >> ================= > >> > >> $ ls -al /sys/fs/bcache/ > >> total 0 > >> drwxr-xr-x 2 root root 0 Feb 25 13:42 . > >> drwxr-xr-x 9 root root 0 Feb 25 13:40 .. > >> --w------- 1 root root 4096 Feb 25 13:40 register > >> --w------- 1 root root 4096 Feb 25 13:40 register_quiet > >> > >> $ file /dev/zram0 > >> /dev/zram0: block special (250/0) > >> > >> $ fdisk -l /dev/zram0 > >> Disk /dev/zram0: 1 GiB, 1073741824 bytes, 262144 sectors > >> > >> $ make-bcache -C /dev/zram0 > >> UUID: 87e63981-7bd8-4cc3-93db-9ca275367c21 > >> Set UUID: 0bba8852-ad4f-41f4-bfa3-679a886a14ad > >> version: 0 > >> nbuckets: 2048 > >> block_size: 8 > >> bucket_size: 1024 > >> nr_in_set: 1 > >> nr_this_dev: 0 > >> first_bucket: 1 > > > > did you `echo /dev/zram0 > /sys/fs/bcache/register` > > and then `echo <CSET-UUID> > /sys/block/bcache0/bcache/attach` > > > > Not sure which UUID is the CSET UUID. Probably > > 0bba8852-ad4f-41f4-bfa3-679a886a14ad. > > > > See attaching bcache0 to a cache: > > https://www.kernel.org/doc/Documentation/bcache.txt > > > > -Eric > > > >> > >> > >> No errors, but nothing in dmesg and contents of /sys/fs/bcache/ remain > >> exactly the same... no UUID. Seems to just silently fail. > >> > >> > >> with HDD - works as expected. > >> ===================== > >> > >> $ fdisk -l /dev/sdf > >> Disk /dev/sdf: 1 GiB, 1073741824 bytes, 2097152 sectors > >> > >> $ file /dev/sdf > >> /dev/sdf: block special (8/80) > >> > >> $ make-bcache -C /dev/sdf > >> UUID: 3234c9e7-8186-4a7c-99a8-ae6a371c6f2c > >> Set UUID: 9a71faf7-a408-4f4d-906e-e5d67e43291f > >> version: 0 > >> nbuckets: 2048 > >> block_size: 1 > >> bucket_size: 1024 > >> nr_in_set: 1 > >> nr_this_dev: 0 > >> first_bucket: 1 > >> > >> $ ls -al /sys/fs/bcache/ > >> total 0 > >> drwxr-xr-x 3 root root 0 Feb 25 13:48 . > >> drwxr-xr-x 9 root root 0 Feb 25 13:40 .. > >> drwxr-xr-x 7 root root 0 Feb 25 13:48 9a71faf7-a408-4f4d-906e-e5d67e43291f > >> --w------- 1 root root 4096 Feb 25 13:40 register > >> --w------- 1 root root 4096 Feb 25 13:40 register_quiet > >> > >> $ dmesg > >> [ 714.168488] bcache: register_cache() registered cache device sdf > >> > >> > >> Thank you. > >> > >> On 24 February 2016 at 15:37, Eric Wheeler <lists@ewheeler.net> wrote: > >> > > >> > On Tue, 16 Feb 2016, Scott McGillivray wrote: > >> > > >> >> Hello > >> >> > >> >> I am using Ubuntu 15.10 with latest nightly 4.5 kernel. Ubuntu creates > >> >> 16 RAM drives as /dev/ram0 - ram16 by default and i am trying to test > >> >> bcache and use one of these as a cache device. > >> >> > >> >> wipefs /dev/sdd > >> >> wipefs /dev/sdd -a > >> >> wipefs /dev/ram0 > >> >> wipefs /dev/ram0 -a > >> >> make-bcache -B /dev/sdd -C /dev/ram0 > >> > > >> > Does it work with /dev/zram0? You would prep it something like this: > >> > > >> > modprobe zram > >> > echo $((1024*1024*1024)) > /sys/block/zram0/disksize # 1GB > >> > make-bcache -C /dev/zram0 > >> > > >> > -Eric > >> > > >> > > >> > > >> >> At this point there were no errors output but there is also no UUID > >> >> entry in /sys/fs/bcache/. Only register and register_quiet. > >> >> > >> >> bache-super-show correctly prints info about both block and cache > >> >> devices when queried but when i try to manually attach the cache > >> >> device with echo cset.uuid > /sys/block/bcache0/bcache/attach i get no > >> >> error but in dmesg i see > >> >> > >> >> bcache: __cached_dev_store() Can't attach > >> >> 3f2521a6-2103-4e2e-a47d-cc56558e8f7d: cache set not found > >> >> > >> >> If i repeat this example but use another sd block device as cache then > >> >> it works OK. > >> >> > >> >> Can anyone confirm if it should be possible to use the ramdisk based > >> >> block device as a caching device with bcache ? > >> >> > >> >> I also tried to use a loop device as cache and that didn't work > >> >> either.. i got "kernel bug" in dmesg for > >> >> drivers/md/bcache/super.c:1812. RIP [] > >> >> cache_alloc.isra.21+0x646/0x670[bcache] > >> >> > >> >> Does bcache need the cache device to be a certain block type i.e sd 8 > >> >> ? Should i be able to use any block device from /proc/devices as a > >> >> cache device ? > >> >> > >> >> The kernel options used for ramdisk are: > >> >> > >> >> CONFIG_BLK_DEV_RAM=y > >> >> CONFIG_BLK_DEV_RAM_COUNT=16 > >> >> CONFIG_BLK_DEV_RAM_SIZE=65536 > >> >> CONFIG_BLK_DEV_RAM_DAX=y > >> >> > >> >> Thank you. > >> >> Scott > >> >> -- > >> >> To unsubscribe from this list: send the line "unsubscribe linux-bcache" in > >> >> the body of a message to majordomo@vger.kernel.org > >> >> More majordomo info at http://vger.kernel.org/majordomo-info.html > >> >> > >> > > >> > > >> > > >> > -- > >> > Eric Wheeler, President eWheeler, Inc. dba Global Linux Security > >> > 888-LINUX26 (888-546-8926) Fax: 503-716-3878 PO Box 25107 > >> > www.GlobalLinuxSecurity.pro Linux since 1996! Portland, OR 97298 > >> > > >> -- > >> To unsubscribe from this list: send the line "unsubscribe linux-bcache" in > >> the body of a message to majordomo@vger.kernel.org > >> More majordomo info at http://vger.kernel.org/majordomo-info.html > >> > ^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: can't use ramdisk as cache device. Receive "Can't attach [UUID]: cache set not found" error 2016-02-25 7:26 ` Eric Wheeler @ 2016-02-25 7:39 ` Eric Wheeler 2016-02-25 8:09 ` Scott McGillivray 0 siblings, 1 reply; 9+ messages in thread From: Eric Wheeler @ 2016-02-25 7:39 UTC (permalink / raw) To: Scott McGillivray; +Cc: linux-bcache On Thu, 25 Feb 2016, Eric Wheeler wrote: > On Thu, 25 Feb 2016, Scott McGillivray wrote: > > > that doesn't work either. It gives the same error from my opening > > post. Although this time it's also giving a new message in dmesg about > > block size. > > > > > > bcache: bch_cached_dev_attach() Couldn't attach sdf: block size less > > than set's block size > > bcache: __cached_dev_store() Can't attach 0bba8852-ad4f-41f4-bfa3-679a886a14ad > > : cache set not found > > > > which is strange because both devices block size are the same > > > > $ blockdev --getbsz /dev/sdf > > 4096 > > > > $ blockdev --getbsz /dev/zram0 > > 4096 > > > Try this: > make-bcache -w 4096 -C /dev/zram0 I'm not sure if -w needs to be called on the backing device too---but if you do then expect to loose data when reformatting. If you decide reformat both backing and cache devices to test, then you might consider aligning your data to your backing volume's stride width with --data-offset NNN while you're at it if you haven't already. -Eric > > > > > > > On 25 February 2016 at 14:44, Eric Wheeler <bcache@lists.ewheeler.net> wrote: > > > On Thu, 25 Feb 2016, Scott McGillivray wrote: > > > > > >> No, doesn't' work either i'm afraid. Below is example of failing > > >> silently with ram disk and succeeded with HDD as cache device. > > >> > > >> Tested with /lib/modules/4.5.0-rc3+/kernel/drivers/md/bcache/bcache.ko > > >> > > >> > > >> with zram - doesn't work > > >> ================= > > >> > > >> $ ls -al /sys/fs/bcache/ > > >> total 0 > > >> drwxr-xr-x 2 root root 0 Feb 25 13:42 . > > >> drwxr-xr-x 9 root root 0 Feb 25 13:40 .. > > >> --w------- 1 root root 4096 Feb 25 13:40 register > > >> --w------- 1 root root 4096 Feb 25 13:40 register_quiet > > >> > > >> $ file /dev/zram0 > > >> /dev/zram0: block special (250/0) > > >> > > >> $ fdisk -l /dev/zram0 > > >> Disk /dev/zram0: 1 GiB, 1073741824 bytes, 262144 sectors > > >> > > >> $ make-bcache -C /dev/zram0 > > >> UUID: 87e63981-7bd8-4cc3-93db-9ca275367c21 > > >> Set UUID: 0bba8852-ad4f-41f4-bfa3-679a886a14ad > > >> version: 0 > > >> nbuckets: 2048 > > >> block_size: 8 > > >> bucket_size: 1024 > > >> nr_in_set: 1 > > >> nr_this_dev: 0 > > >> first_bucket: 1 > > > > > > did you `echo /dev/zram0 > /sys/fs/bcache/register` > > > and then `echo <CSET-UUID> > /sys/block/bcache0/bcache/attach` > > > > > > Not sure which UUID is the CSET UUID. Probably > > > 0bba8852-ad4f-41f4-bfa3-679a886a14ad. > > > > > > See attaching bcache0 to a cache: > > > https://www.kernel.org/doc/Documentation/bcache.txt > > > > > > -Eric > > > > > >> > > >> > > >> No errors, but nothing in dmesg and contents of /sys/fs/bcache/ remain > > >> exactly the same... no UUID. Seems to just silently fail. > > >> > > >> > > >> with HDD - works as expected. > > >> ===================== > > >> > > >> $ fdisk -l /dev/sdf > > >> Disk /dev/sdf: 1 GiB, 1073741824 bytes, 2097152 sectors > > >> > > >> $ file /dev/sdf > > >> /dev/sdf: block special (8/80) > > >> > > >> $ make-bcache -C /dev/sdf > > >> UUID: 3234c9e7-8186-4a7c-99a8-ae6a371c6f2c > > >> Set UUID: 9a71faf7-a408-4f4d-906e-e5d67e43291f > > >> version: 0 > > >> nbuckets: 2048 > > >> block_size: 1 > > >> bucket_size: 1024 > > >> nr_in_set: 1 > > >> nr_this_dev: 0 > > >> first_bucket: 1 > > >> > > >> $ ls -al /sys/fs/bcache/ > > >> total 0 > > >> drwxr-xr-x 3 root root 0 Feb 25 13:48 . > > >> drwxr-xr-x 9 root root 0 Feb 25 13:40 .. > > >> drwxr-xr-x 7 root root 0 Feb 25 13:48 9a71faf7-a408-4f4d-906e-e5d67e43291f > > >> --w------- 1 root root 4096 Feb 25 13:40 register > > >> --w------- 1 root root 4096 Feb 25 13:40 register_quiet > > >> > > >> $ dmesg > > >> [ 714.168488] bcache: register_cache() registered cache device sdf > > >> > > >> > > >> Thank you. > > >> > > >> On 24 February 2016 at 15:37, Eric Wheeler <lists@ewheeler.net> wrote: > > >> > > > >> > On Tue, 16 Feb 2016, Scott McGillivray wrote: > > >> > > > >> >> Hello > > >> >> > > >> >> I am using Ubuntu 15.10 with latest nightly 4.5 kernel. Ubuntu creates > > >> >> 16 RAM drives as /dev/ram0 - ram16 by default and i am trying to test > > >> >> bcache and use one of these as a cache device. > > >> >> > > >> >> wipefs /dev/sdd > > >> >> wipefs /dev/sdd -a > > >> >> wipefs /dev/ram0 > > >> >> wipefs /dev/ram0 -a > > >> >> make-bcache -B /dev/sdd -C /dev/ram0 > > >> > > > >> > Does it work with /dev/zram0? You would prep it something like this: > > >> > > > >> > modprobe zram > > >> > echo $((1024*1024*1024)) > /sys/block/zram0/disksize # 1GB > > >> > make-bcache -C /dev/zram0 > > >> > > > >> > -Eric > > >> > > > >> > > > >> > > > >> >> At this point there were no errors output but there is also no UUID > > >> >> entry in /sys/fs/bcache/. Only register and register_quiet. > > >> >> > > >> >> bache-super-show correctly prints info about both block and cache > > >> >> devices when queried but when i try to manually attach the cache > > >> >> device with echo cset.uuid > /sys/block/bcache0/bcache/attach i get no > > >> >> error but in dmesg i see > > >> >> > > >> >> bcache: __cached_dev_store() Can't attach > > >> >> 3f2521a6-2103-4e2e-a47d-cc56558e8f7d: cache set not found > > >> >> > > >> >> If i repeat this example but use another sd block device as cache then > > >> >> it works OK. > > >> >> > > >> >> Can anyone confirm if it should be possible to use the ramdisk based > > >> >> block device as a caching device with bcache ? > > >> >> > > >> >> I also tried to use a loop device as cache and that didn't work > > >> >> either.. i got "kernel bug" in dmesg for > > >> >> drivers/md/bcache/super.c:1812. RIP [] > > >> >> cache_alloc.isra.21+0x646/0x670[bcache] > > >> >> > > >> >> Does bcache need the cache device to be a certain block type i.e sd 8 > > >> >> ? Should i be able to use any block device from /proc/devices as a > > >> >> cache device ? > > >> >> > > >> >> The kernel options used for ramdisk are: > > >> >> > > >> >> CONFIG_BLK_DEV_RAM=y > > >> >> CONFIG_BLK_DEV_RAM_COUNT=16 > > >> >> CONFIG_BLK_DEV_RAM_SIZE=65536 > > >> >> CONFIG_BLK_DEV_RAM_DAX=y > > >> >> > > >> >> Thank you. > > >> >> Scott > > >> >> -- > > >> >> To unsubscribe from this list: send the line "unsubscribe linux-bcache" in > > >> >> the body of a message to majordomo@vger.kernel.org > > >> >> More majordomo info at http://vger.kernel.org/majordomo-info.html > > >> >> > > >> > > > >> > > > >> > > > >> > -- > > >> > Eric Wheeler, President eWheeler, Inc. dba Global Linux Security > > >> > 888-LINUX26 (888-546-8926) Fax: 503-716-3878 PO Box 25107 > > >> > www.GlobalLinuxSecurity.pro Linux since 1996! Portland, OR 97298 > > >> > > > >> -- > > >> To unsubscribe from this list: send the line "unsubscribe linux-bcache" in > > >> the body of a message to majordomo@vger.kernel.org > > >> More majordomo info at http://vger.kernel.org/majordomo-info.html > > >> > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-bcache" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > ^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: can't use ramdisk as cache device. Receive "Can't attach [UUID]: cache set not found" error 2016-02-25 7:39 ` Eric Wheeler @ 2016-02-25 8:09 ` Scott McGillivray 2016-02-25 8:15 ` Eric Wheeler 0 siblings, 1 reply; 9+ messages in thread From: Scott McGillivray @ 2016-02-25 8:09 UTC (permalink / raw) To: Eric Wheeler; +Cc: linux-bcache yes thank you. When using zram and -w 4096 it worked as expected. But when i re-tested with /dev/ram0 which is using the BLK_DEV_RAM/brd ram device as cache. The make-bcache worked OK but when i tried to register the device via "echo /dev/ram0 > /sys/fs/bcache/register" it blows up with below error in dmesg. Call Trace: [ 8460.086681] [<ffffffff812f8ae7>] kobj_attr_store+0xf/0x19 [ 8460.086685] [<ffffffff811fd737>] sysfs_kf_write+0x3e/0x40 [ 8460.086689] [<ffffffff811fcc40>] kernfs_fop_write+0xe9/0x136 [ 8460.086694] [<ffffffff8119b0ed>] __vfs_write+0x28/0xa7 [ 8460.086699] [<ffffffff81286ed3>] ? security_file_permission+0x3b/0x42 [ 8460.086705] [<ffffffff8109b30c>] ? percpu_down_read+0x1f/0x41 [ 8460.086708] [<ffffffff8119d604>] ? __sb_start_write+0x24/0x41 [ 8460.086712] [<ffffffff8119bba2>] vfs_write+0x8f/0xe5 [ 8460.086715] [<ffffffff8119c534>] SyS_write+0x46/0x79 [ 8460.086720] [<ffffffff81645176>] entry_SYSCALL_64_fastpath+0x16/0x75 [ 8460.086722] Code: 00 48 83 ff 04 77 09 49 89 bd b8 0a 00 00 eb 0f e8 c6 c3 ff ff 48 ff c8 49 89 85 b8 0a 00 00 49 8b bd b8 0a 00 00 48 85 ff 75 02 <0f> 0b 48 ff c7 e8 a6 c3 ff ff 48 8d 14 c5 00 00 00 00 48 ff c8 [ 8460.086766] RIP [<ffffffffc00e832f>] register_bcache+0xe27/0x1423 [bcache] On 25 February 2016 at 15:39, Eric Wheeler <bcache@lists.ewheeler.net> wrote: > On Thu, 25 Feb 2016, Eric Wheeler wrote: > >> On Thu, 25 Feb 2016, Scott McGillivray wrote: >> >> > that doesn't work either. It gives the same error from my opening >> > post. Although this time it's also giving a new message in dmesg about >> > block size. >> > >> > >> > bcache: bch_cached_dev_attach() Couldn't attach sdf: block size less >> > than set's block size >> > bcache: __cached_dev_store() Can't attach 0bba8852-ad4f-41f4-bfa3-679a886a14ad >> > : cache set not found >> > >> > which is strange because both devices block size are the same >> > >> > $ blockdev --getbsz /dev/sdf >> > 4096 >> > >> > $ blockdev --getbsz /dev/zram0 >> > 4096 >> >> >> Try this: >> make-bcache -w 4096 -C /dev/zram0 > > I'm not sure if -w needs to be called on the backing device too---but if > you do then expect to loose data when reformatting. > > If you decide reformat both backing and cache devices to test, then you > might consider aligning your data to your backing volume's stride width > with --data-offset NNN while you're at it if you haven't already. > > -Eric > >> >> > >> > >> > On 25 February 2016 at 14:44, Eric Wheeler <bcache@lists.ewheeler.net> wrote: >> > > On Thu, 25 Feb 2016, Scott McGillivray wrote: >> > > >> > >> No, doesn't' work either i'm afraid. Below is example of failing >> > >> silently with ram disk and succeeded with HDD as cache device. >> > >> >> > >> Tested with /lib/modules/4.5.0-rc3+/kernel/drivers/md/bcache/bcache.ko >> > >> >> > >> >> > >> with zram - doesn't work >> > >> ================= >> > >> >> > >> $ ls -al /sys/fs/bcache/ >> > >> total 0 >> > >> drwxr-xr-x 2 root root 0 Feb 25 13:42 . >> > >> drwxr-xr-x 9 root root 0 Feb 25 13:40 .. >> > >> --w------- 1 root root 4096 Feb 25 13:40 register >> > >> --w------- 1 root root 4096 Feb 25 13:40 register_quiet >> > >> >> > >> $ file /dev/zram0 >> > >> /dev/zram0: block special (250/0) >> > >> >> > >> $ fdisk -l /dev/zram0 >> > >> Disk /dev/zram0: 1 GiB, 1073741824 bytes, 262144 sectors >> > >> >> > >> $ make-bcache -C /dev/zram0 >> > >> UUID: 87e63981-7bd8-4cc3-93db-9ca275367c21 >> > >> Set UUID: 0bba8852-ad4f-41f4-bfa3-679a886a14ad >> > >> version: 0 >> > >> nbuckets: 2048 >> > >> block_size: 8 >> > >> bucket_size: 1024 >> > >> nr_in_set: 1 >> > >> nr_this_dev: 0 >> > >> first_bucket: 1 >> > > >> > > did you `echo /dev/zram0 > /sys/fs/bcache/register` >> > > and then `echo <CSET-UUID> > /sys/block/bcache0/bcache/attach` >> > > >> > > Not sure which UUID is the CSET UUID. Probably >> > > 0bba8852-ad4f-41f4-bfa3-679a886a14ad. >> > > >> > > See attaching bcache0 to a cache: >> > > https://www.kernel.org/doc/Documentation/bcache.txt >> > > >> > > -Eric >> > > >> > >> >> > >> >> > >> No errors, but nothing in dmesg and contents of /sys/fs/bcache/ remain >> > >> exactly the same... no UUID. Seems to just silently fail. >> > >> >> > >> >> > >> with HDD - works as expected. >> > >> ===================== >> > >> >> > >> $ fdisk -l /dev/sdf >> > >> Disk /dev/sdf: 1 GiB, 1073741824 bytes, 2097152 sectors >> > >> >> > >> $ file /dev/sdf >> > >> /dev/sdf: block special (8/80) >> > >> >> > >> $ make-bcache -C /dev/sdf >> > >> UUID: 3234c9e7-8186-4a7c-99a8-ae6a371c6f2c >> > >> Set UUID: 9a71faf7-a408-4f4d-906e-e5d67e43291f >> > >> version: 0 >> > >> nbuckets: 2048 >> > >> block_size: 1 >> > >> bucket_size: 1024 >> > >> nr_in_set: 1 >> > >> nr_this_dev: 0 >> > >> first_bucket: 1 >> > >> >> > >> $ ls -al /sys/fs/bcache/ >> > >> total 0 >> > >> drwxr-xr-x 3 root root 0 Feb 25 13:48 . >> > >> drwxr-xr-x 9 root root 0 Feb 25 13:40 .. >> > >> drwxr-xr-x 7 root root 0 Feb 25 13:48 9a71faf7-a408-4f4d-906e-e5d67e43291f >> > >> --w------- 1 root root 4096 Feb 25 13:40 register >> > >> --w------- 1 root root 4096 Feb 25 13:40 register_quiet >> > >> >> > >> $ dmesg >> > >> [ 714.168488] bcache: register_cache() registered cache device sdf >> > >> >> > >> >> > >> Thank you. >> > >> >> > >> On 24 February 2016 at 15:37, Eric Wheeler <lists@ewheeler.net> wrote: >> > >> > >> > >> > On Tue, 16 Feb 2016, Scott McGillivray wrote: >> > >> > >> > >> >> Hello >> > >> >> >> > >> >> I am using Ubuntu 15.10 with latest nightly 4.5 kernel. Ubuntu creates >> > >> >> 16 RAM drives as /dev/ram0 - ram16 by default and i am trying to test >> > >> >> bcache and use one of these as a cache device. >> > >> >> >> > >> >> wipefs /dev/sdd >> > >> >> wipefs /dev/sdd -a >> > >> >> wipefs /dev/ram0 >> > >> >> wipefs /dev/ram0 -a >> > >> >> make-bcache -B /dev/sdd -C /dev/ram0 >> > >> > >> > >> > Does it work with /dev/zram0? You would prep it something like this: >> > >> > >> > >> > modprobe zram >> > >> > echo $((1024*1024*1024)) > /sys/block/zram0/disksize # 1GB >> > >> > make-bcache -C /dev/zram0 >> > >> > >> > >> > -Eric >> > >> > >> > >> > >> > >> > >> > >> >> At this point there were no errors output but there is also no UUID >> > >> >> entry in /sys/fs/bcache/. Only register and register_quiet. >> > >> >> >> > >> >> bache-super-show correctly prints info about both block and cache >> > >> >> devices when queried but when i try to manually attach the cache >> > >> >> device with echo cset.uuid > /sys/block/bcache0/bcache/attach i get no >> > >> >> error but in dmesg i see >> > >> >> >> > >> >> bcache: __cached_dev_store() Can't attach >> > >> >> 3f2521a6-2103-4e2e-a47d-cc56558e8f7d: cache set not found >> > >> >> >> > >> >> If i repeat this example but use another sd block device as cache then >> > >> >> it works OK. >> > >> >> >> > >> >> Can anyone confirm if it should be possible to use the ramdisk based >> > >> >> block device as a caching device with bcache ? >> > >> >> >> > >> >> I also tried to use a loop device as cache and that didn't work >> > >> >> either.. i got "kernel bug" in dmesg for >> > >> >> drivers/md/bcache/super.c:1812. RIP [] >> > >> >> cache_alloc.isra.21+0x646/0x670[bcache] >> > >> >> >> > >> >> Does bcache need the cache device to be a certain block type i.e sd 8 >> > >> >> ? Should i be able to use any block device from /proc/devices as a >> > >> >> cache device ? >> > >> >> >> > >> >> The kernel options used for ramdisk are: >> > >> >> >> > >> >> CONFIG_BLK_DEV_RAM=y >> > >> >> CONFIG_BLK_DEV_RAM_COUNT=16 >> > >> >> CONFIG_BLK_DEV_RAM_SIZE=65536 >> > >> >> CONFIG_BLK_DEV_RAM_DAX=y >> > >> >> >> > >> >> Thank you. >> > >> >> Scott >> > >> >> -- >> > >> >> To unsubscribe from this list: send the line "unsubscribe linux-bcache" in >> > >> >> the body of a message to majordomo@vger.kernel.org >> > >> >> More majordomo info at http://vger.kernel.org/majordomo-info.html >> > >> >> >> > >> > >> > >> > >> > >> > >> > >> > -- >> > >> > Eric Wheeler, President eWheeler, Inc. dba Global Linux Security >> > >> > 888-LINUX26 (888-546-8926) Fax: 503-716-3878 PO Box 25107 >> > >> > www.GlobalLinuxSecurity.pro Linux since 1996! Portland, OR 97298 >> > >> > >> > >> -- >> > >> To unsubscribe from this list: send the line "unsubscribe linux-bcache" in >> > >> the body of a message to majordomo@vger.kernel.org >> > >> More majordomo info at http://vger.kernel.org/majordomo-info.html >> > >> >> > >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-bcache" in >> the body of a message to majordomo@vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html >> ^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: can't use ramdisk as cache device. Receive "Can't attach [UUID]: cache set not found" error 2016-02-25 8:09 ` Scott McGillivray @ 2016-02-25 8:15 ` Eric Wheeler 0 siblings, 0 replies; 9+ messages in thread From: Eric Wheeler @ 2016-02-25 8:15 UTC (permalink / raw) To: Scott McGillivray; +Cc: linux-bcache On Thu, 25 Feb 2016, Scott McGillivray wrote: > yes thank you. When using zram and -w 4096 it worked as expected. > > But when i re-tested with /dev/ram0 which is using the BLK_DEV_RAM/brd > ram device as cache. The make-bcache worked OK but when i tried to > register the device via "echo /dev/ram0 > /sys/fs/bcache/register" it > blows up with below error in dmesg. > > Call Trace: > [ 8460.086681] [<ffffffff812f8ae7>] kobj_attr_store+0xf/0x19 > [ 8460.086685] [<ffffffff811fd737>] sysfs_kf_write+0x3e/0x40 > [ 8460.086689] [<ffffffff811fcc40>] kernfs_fop_write+0xe9/0x136 > [ 8460.086694] [<ffffffff8119b0ed>] __vfs_write+0x28/0xa7 > [ 8460.086699] [<ffffffff81286ed3>] ? security_file_permission+0x3b/0x42 > [ 8460.086705] [<ffffffff8109b30c>] ? percpu_down_read+0x1f/0x41 > [ 8460.086708] [<ffffffff8119d604>] ? __sb_start_write+0x24/0x41 > [ 8460.086712] [<ffffffff8119bba2>] vfs_write+0x8f/0xe5 > [ 8460.086715] [<ffffffff8119c534>] SyS_write+0x46/0x79 > [ 8460.086720] [<ffffffff81645176>] entry_SYSCALL_64_fastpath+0x16/0x75 > [ 8460.086722] Code: 00 48 83 ff 04 77 09 49 89 bd b8 0a 00 00 eb 0f > e8 c6 c3 ff ff 48 ff c8 49 89 85 b8 0a 00 00 49 8b bd b8 0a 00 00 48 > 85 ff 75 02 <0f> 0b 48 ff c7 e8 a6 c3 ff ff 48 8d 14 c5 00 00 00 00 48 > ff c8 > [ 8460.086766] RIP [<ffffffffc00e832f>] register_bcache+0xe27/0x1423 [bcache] I just posted a patch in the thread "Re: bcache: register_cache() error opening sdh2" that might cleanup register_cache() error handling, and might give a better error---but ram0 devices are rather old and might not do what you want. I seem to remember they need to be initialized by dd if=/dev/zero of=/dev/ram0 or some such thing. I always seem to have trouble with /dev/ramX devices. You might be better off using /dev/loop0 and loopback a file in /dev/shm/ or /dev/hugepages/. -- Eric Wheeler, President eWheeler, Inc. dba Global Linux Security 888-LINUX26 (888-546-8926) Fax: 503-716-3878 PO Box 25107 www.GlobalLinuxSecurity.pro Linux since 1996! Portland, OR 97298 > > > > On 25 February 2016 at 15:39, Eric Wheeler <bcache@lists.ewheeler.net> wrote: > > On Thu, 25 Feb 2016, Eric Wheeler wrote: > > > >> On Thu, 25 Feb 2016, Scott McGillivray wrote: > >> > >> > that doesn't work either. It gives the same error from my opening > >> > post. Although this time it's also giving a new message in dmesg about > >> > block size. > >> > > >> > > >> > bcache: bch_cached_dev_attach() Couldn't attach sdf: block size less > >> > than set's block size > >> > bcache: __cached_dev_store() Can't attach 0bba8852-ad4f-41f4-bfa3-679a886a14ad > >> > : cache set not found > >> > > >> > which is strange because both devices block size are the same > >> > > >> > $ blockdev --getbsz /dev/sdf > >> > 4096 > >> > > >> > $ blockdev --getbsz /dev/zram0 > >> > 4096 > >> > >> > >> Try this: > >> make-bcache -w 4096 -C /dev/zram0 > > > > I'm not sure if -w needs to be called on the backing device too---but if > > you do then expect to loose data when reformatting. > > > > If you decide reformat both backing and cache devices to test, then you > > might consider aligning your data to your backing volume's stride width > > with --data-offset NNN while you're at it if you haven't already. > > > > -Eric > > > >> > >> > > >> > > >> > On 25 February 2016 at 14:44, Eric Wheeler <bcache@lists.ewheeler.net> wrote: > >> > > On Thu, 25 Feb 2016, Scott McGillivray wrote: > >> > > > >> > >> No, doesn't' work either i'm afraid. Below is example of failing > >> > >> silently with ram disk and succeeded with HDD as cache device. > >> > >> > >> > >> Tested with /lib/modules/4.5.0-rc3+/kernel/drivers/md/bcache/bcache.ko > >> > >> > >> > >> > >> > >> with zram - doesn't work > >> > >> ================= > >> > >> > >> > >> $ ls -al /sys/fs/bcache/ > >> > >> total 0 > >> > >> drwxr-xr-x 2 root root 0 Feb 25 13:42 . > >> > >> drwxr-xr-x 9 root root 0 Feb 25 13:40 .. > >> > >> --w------- 1 root root 4096 Feb 25 13:40 register > >> > >> --w------- 1 root root 4096 Feb 25 13:40 register_quiet > >> > >> > >> > >> $ file /dev/zram0 > >> > >> /dev/zram0: block special (250/0) > >> > >> > >> > >> $ fdisk -l /dev/zram0 > >> > >> Disk /dev/zram0: 1 GiB, 1073741824 bytes, 262144 sectors > >> > >> > >> > >> $ make-bcache -C /dev/zram0 > >> > >> UUID: 87e63981-7bd8-4cc3-93db-9ca275367c21 > >> > >> Set UUID: 0bba8852-ad4f-41f4-bfa3-679a886a14ad > >> > >> version: 0 > >> > >> nbuckets: 2048 > >> > >> block_size: 8 > >> > >> bucket_size: 1024 > >> > >> nr_in_set: 1 > >> > >> nr_this_dev: 0 > >> > >> first_bucket: 1 > >> > > > >> > > did you `echo /dev/zram0 > /sys/fs/bcache/register` > >> > > and then `echo <CSET-UUID> > /sys/block/bcache0/bcache/attach` > >> > > > >> > > Not sure which UUID is the CSET UUID. Probably > >> > > 0bba8852-ad4f-41f4-bfa3-679a886a14ad. > >> > > > >> > > See attaching bcache0 to a cache: > >> > > https://www.kernel.org/doc/Documentation/bcache.txt > >> > > > >> > > -Eric > >> > > > >> > >> > >> > >> > >> > >> No errors, but nothing in dmesg and contents of /sys/fs/bcache/ remain > >> > >> exactly the same... no UUID. Seems to just silently fail. > >> > >> > >> > >> > >> > >> with HDD - works as expected. > >> > >> ===================== > >> > >> > >> > >> $ fdisk -l /dev/sdf > >> > >> Disk /dev/sdf: 1 GiB, 1073741824 bytes, 2097152 sectors > >> > >> > >> > >> $ file /dev/sdf > >> > >> /dev/sdf: block special (8/80) > >> > >> > >> > >> $ make-bcache -C /dev/sdf > >> > >> UUID: 3234c9e7-8186-4a7c-99a8-ae6a371c6f2c > >> > >> Set UUID: 9a71faf7-a408-4f4d-906e-e5d67e43291f > >> > >> version: 0 > >> > >> nbuckets: 2048 > >> > >> block_size: 1 > >> > >> bucket_size: 1024 > >> > >> nr_in_set: 1 > >> > >> nr_this_dev: 0 > >> > >> first_bucket: 1 > >> > >> > >> > >> $ ls -al /sys/fs/bcache/ > >> > >> total 0 > >> > >> drwxr-xr-x 3 root root 0 Feb 25 13:48 . > >> > >> drwxr-xr-x 9 root root 0 Feb 25 13:40 .. > >> > >> drwxr-xr-x 7 root root 0 Feb 25 13:48 9a71faf7-a408-4f4d-906e-e5d67e43291f > >> > >> --w------- 1 root root 4096 Feb 25 13:40 register > >> > >> --w------- 1 root root 4096 Feb 25 13:40 register_quiet > >> > >> > >> > >> $ dmesg > >> > >> [ 714.168488] bcache: register_cache() registered cache device sdf > >> > >> > >> > >> > >> > >> Thank you. > >> > >> > >> > >> On 24 February 2016 at 15:37, Eric Wheeler <lists@ewheeler.net> wrote: > >> > >> > > >> > >> > On Tue, 16 Feb 2016, Scott McGillivray wrote: > >> > >> > > >> > >> >> Hello > >> > >> >> > >> > >> >> I am using Ubuntu 15.10 with latest nightly 4.5 kernel. Ubuntu creates > >> > >> >> 16 RAM drives as /dev/ram0 - ram16 by default and i am trying to test > >> > >> >> bcache and use one of these as a cache device. > >> > >> >> > >> > >> >> wipefs /dev/sdd > >> > >> >> wipefs /dev/sdd -a > >> > >> >> wipefs /dev/ram0 > >> > >> >> wipefs /dev/ram0 -a > >> > >> >> make-bcache -B /dev/sdd -C /dev/ram0 > >> > >> > > >> > >> > Does it work with /dev/zram0? You would prep it something like this: > >> > >> > > >> > >> > modprobe zram > >> > >> > echo $((1024*1024*1024)) > /sys/block/zram0/disksize # 1GB > >> > >> > make-bcache -C /dev/zram0 > >> > >> > > >> > >> > -Eric > >> > >> > > >> > >> > > >> > >> > > >> > >> >> At this point there were no errors output but there is also no UUID > >> > >> >> entry in /sys/fs/bcache/. Only register and register_quiet. > >> > >> >> > >> > >> >> bache-super-show correctly prints info about both block and cache > >> > >> >> devices when queried but when i try to manually attach the cache > >> > >> >> device with echo cset.uuid > /sys/block/bcache0/bcache/attach i get no > >> > >> >> error but in dmesg i see > >> > >> >> > >> > >> >> bcache: __cached_dev_store() Can't attach > >> > >> >> 3f2521a6-2103-4e2e-a47d-cc56558e8f7d: cache set not found > >> > >> >> > >> > >> >> If i repeat this example but use another sd block device as cache then > >> > >> >> it works OK. > >> > >> >> > >> > >> >> Can anyone confirm if it should be possible to use the ramdisk based > >> > >> >> block device as a caching device with bcache ? > >> > >> >> > >> > >> >> I also tried to use a loop device as cache and that didn't work > >> > >> >> either.. i got "kernel bug" in dmesg for > >> > >> >> drivers/md/bcache/super.c:1812. RIP [] > >> > >> >> cache_alloc.isra.21+0x646/0x670[bcache] > >> > >> >> > >> > >> >> Does bcache need the cache device to be a certain block type i.e sd 8 > >> > >> >> ? Should i be able to use any block device from /proc/devices as a > >> > >> >> cache device ? > >> > >> >> > >> > >> >> The kernel options used for ramdisk are: > >> > >> >> > >> > >> >> CONFIG_BLK_DEV_RAM=y > >> > >> >> CONFIG_BLK_DEV_RAM_COUNT=16 > >> > >> >> CONFIG_BLK_DEV_RAM_SIZE=65536 > >> > >> >> CONFIG_BLK_DEV_RAM_DAX=y > >> > >> >> > >> > >> >> Thank you. > >> > >> >> Scott > >> > >> >> -- > >> > >> >> To unsubscribe from this list: send the line "unsubscribe linux-bcache" in > >> > >> >> the body of a message to majordomo@vger.kernel.org > >> > >> >> More majordomo info at http://vger.kernel.org/majordomo-info.html > >> > >> >> > >> > >> > > >> > >> > > >> > >> > > >> > >> > -- > >> > >> > Eric Wheeler, President eWheeler, Inc. dba Global Linux Security > >> > >> > 888-LINUX26 (888-546-8926) Fax: 503-716-3878 PO Box 25107 > >> > >> > www.GlobalLinuxSecurity.pro Linux since 1996! Portland, OR 97298 > >> > >> > > >> > >> -- > >> > >> To unsubscribe from this list: send the line "unsubscribe linux-bcache" in > >> > >> the body of a message to majordomo@vger.kernel.org > >> > >> More majordomo info at http://vger.kernel.org/majordomo-info.html > >> > >> > >> > > >> -- > >> To unsubscribe from this list: send the line "unsubscribe linux-bcache" in > >> the body of a message to majordomo@vger.kernel.org > >> More majordomo info at http://vger.kernel.org/majordomo-info.html > >> > -- > To unsubscribe from this list: send the line "unsubscribe linux-bcache" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > ^ permalink raw reply [flat|nested] 9+ messages in thread
end of thread, other threads:[~2016-02-25 8:15 UTC | newest] Thread overview: 9+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2016-02-16 2:40 can't use ramdisk as cache device. Receive "Can't attach [UUID]: cache set not found" error Scott McGillivray 2016-02-24 7:37 ` Eric Wheeler 2016-02-25 5:55 ` Scott McGillivray 2016-02-25 6:44 ` Eric Wheeler 2016-02-25 7:06 ` Scott McGillivray 2016-02-25 7:26 ` Eric Wheeler 2016-02-25 7:39 ` Eric Wheeler 2016-02-25 8:09 ` Scott McGillivray 2016-02-25 8:15 ` Eric Wheeler
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