* writeback mode behaviour on proper shut down @ 2016-04-26 9:26 ching lu 2016-04-26 19:57 ` Eric Wheeler 0 siblings, 1 reply; 6+ messages in thread From: ching lu @ 2016-04-26 9:26 UTC (permalink / raw) To: linux-bcache Hi all, if i have 1 SSD caching 1 HDD using bcache, the cache mode is writeback if the PC shutdown/unmount normally, will all dirty data in the cache be flushed to backing device before poweroff? i am afraid that SSD lose data if left without power for a long time. e.g. hoilday. Thanks in advance, C ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: writeback mode behaviour on proper shut down 2016-04-26 9:26 writeback mode behaviour on proper shut down ching lu @ 2016-04-26 19:57 ` Eric Wheeler 2016-04-27 1:45 ` ching lu 0 siblings, 1 reply; 6+ messages in thread From: Eric Wheeler @ 2016-04-26 19:57 UTC (permalink / raw) To: ching lu; +Cc: linux-bcache On Tue, 26 Apr 2016, ching lu wrote: > Hi all, > > if i have 1 SSD caching 1 HDD using bcache, the cache mode is writeback > > if the PC shutdown/unmount normally, will all dirty data in the cache > be flushed to backing device before poweroff? No, it will remain in the cache. > i am afraid that SSD lose data if left without power for a long time. > e.g. hoilday. Wouldn't your data be retained if you used the SSD alone? SSDs should be stable in a powered off state unless it is a bad device. There exist RAM-based disks that may be volatile, but that is unlikely to be your situation. -- Eric Wheeler > > Thanks in advance, > C > -- > 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] 6+ messages in thread
* Re: writeback mode behaviour on proper shut down 2016-04-26 19:57 ` Eric Wheeler @ 2016-04-27 1:45 ` ching lu 2016-04-27 2:10 ` Eric Wheeler 0 siblings, 1 reply; 6+ messages in thread From: ching lu @ 2016-04-27 1:45 UTC (permalink / raw) To: Eric Wheeler; +Cc: linux-bcache is there any command for forcing flushing cache or invalidate cache? On Wed, Apr 27, 2016 at 3:57 AM, Eric Wheeler <bcache@lists.ewheeler.net> wrote: > On Tue, 26 Apr 2016, ching lu wrote: > >> Hi all, >> >> if i have 1 SSD caching 1 HDD using bcache, the cache mode is writeback >> >> if the PC shutdown/unmount normally, will all dirty data in the cache >> be flushed to backing device before poweroff? > > No, it will remain in the cache. > >> i am afraid that SSD lose data if left without power for a long time. >> e.g. hoilday. > > Wouldn't your data be retained if you used the SSD alone? SSDs should be > stable in a powered off state unless it is a bad device. > > There exist RAM-based disks that may be volatile, but that is unlikely to > be your situation. > > -- > Eric Wheeler > >> >> Thanks in advance, >> C >> -- >> 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] 6+ messages in thread
* Re: writeback mode behaviour on proper shut down 2016-04-27 1:45 ` ching lu @ 2016-04-27 2:10 ` Eric Wheeler 2016-04-28 3:55 ` ching lu 0 siblings, 1 reply; 6+ messages in thread From: Eric Wheeler @ 2016-04-27 2:10 UTC (permalink / raw) To: ching lu; +Cc: linux-bcache On Wed, 27 Apr 2016, ching lu wrote: > is there any command for forcing flushing cache or invalidate cache? I think you would benefit from reading this: https://www.kernel.org/doc/Documentation/bcache.txt -- Eric Wheeler > > On Wed, Apr 27, 2016 at 3:57 AM, Eric Wheeler <bcache@lists.ewheeler.net> wrote: > > On Tue, 26 Apr 2016, ching lu wrote: > > > >> Hi all, > >> > >> if i have 1 SSD caching 1 HDD using bcache, the cache mode is writeback > >> > >> if the PC shutdown/unmount normally, will all dirty data in the cache > >> be flushed to backing device before poweroff? > > > > No, it will remain in the cache. > > > >> i am afraid that SSD lose data if left without power for a long time. > >> e.g. hoilday. > > > > Wouldn't your data be retained if you used the SSD alone? SSDs should be > > stable in a powered off state unless it is a bad device. > > > > There exist RAM-based disks that may be volatile, but that is unlikely to > > be your situation. > > > > -- > > Eric Wheeler > > > >> > >> Thanks in advance, > >> C > >> -- > >> 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] 6+ messages in thread
* Re: writeback mode behaviour on proper shut down 2016-04-27 2:10 ` Eric Wheeler @ 2016-04-28 3:55 ` ching lu 2016-05-11 1:14 ` Eric Wheeler 0 siblings, 1 reply; 6+ messages in thread From: ching lu @ 2016-04-28 3:55 UTC (permalink / raw) To: Eric Wheeler; +Cc: linux-bcache is there any sysfs attribute storing the list of all attached cache devices? i would like to write a script to force flushing cache by stopping them all "echo 1 > /sys/fs/bcache/<cset-uuid>/stop" Furthermore, do the statement return only after the cache device is stopped or i need to poll until "/sys/fs/bcache/<cset-uuid>/bdev*/state"="clean" On Wed, Apr 27, 2016 at 10:10 AM, Eric Wheeler <bcache@lists.ewheeler.net> wrote: > > On Wed, 27 Apr 2016, ching lu wrote: > >> is there any command for forcing flushing cache or invalidate cache? > > I think you would benefit from reading this: > > https://www.kernel.org/doc/Documentation/bcache.txt > > > -- > Eric Wheeler > > > >> >> On Wed, Apr 27, 2016 at 3:57 AM, Eric Wheeler <bcache@lists.ewheeler.net> wrote: >> > On Tue, 26 Apr 2016, ching lu wrote: >> > >> >> Hi all, >> >> >> >> if i have 1 SSD caching 1 HDD using bcache, the cache mode is writeback >> >> >> >> if the PC shutdown/unmount normally, will all dirty data in the cache >> >> be flushed to backing device before poweroff? >> > >> > No, it will remain in the cache. >> > >> >> i am afraid that SSD lose data if left without power for a long time. >> >> e.g. hoilday. >> > >> > Wouldn't your data be retained if you used the SSD alone? SSDs should be >> > stable in a powered off state unless it is a bad device. >> > >> > There exist RAM-based disks that may be volatile, but that is unlikely to >> > be your situation. >> > >> > -- >> > Eric Wheeler >> > >> >> >> >> Thanks in advance, >> >> C >> >> -- >> >> 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] 6+ messages in thread
* Re: writeback mode behaviour on proper shut down 2016-04-28 3:55 ` ching lu @ 2016-05-11 1:14 ` Eric Wheeler 0 siblings, 0 replies; 6+ messages in thread From: Eric Wheeler @ 2016-05-11 1:14 UTC (permalink / raw) To: ching lu; +Cc: linux-bcache On Thu, 28 Apr 2016, ching lu wrote: > is there any sysfs attribute storing the list of all attached cache > devices? i would like to write a script to force flushing cache by > stopping them all I don't think so, but you could scan sysfs easy enough. -- Eric Wheeler > > "echo 1 > /sys/fs/bcache/<cset-uuid>/stop" > > Furthermore, do the statement return only after the cache device is stopped > or i need to poll until "/sys/fs/bcache/<cset-uuid>/bdev*/state"="clean" > > On Wed, Apr 27, 2016 at 10:10 AM, Eric Wheeler > <bcache@lists.ewheeler.net> wrote: > > > > On Wed, 27 Apr 2016, ching lu wrote: > > > >> is there any command for forcing flushing cache or invalidate cache? > > > > I think you would benefit from reading this: > > > > https://www.kernel.org/doc/Documentation/bcache.txt > > > > > > -- > > Eric Wheeler > > > > > > > >> > >> On Wed, Apr 27, 2016 at 3:57 AM, Eric Wheeler <bcache@lists.ewheeler.net> wrote: > >> > On Tue, 26 Apr 2016, ching lu wrote: > >> > > >> >> Hi all, > >> >> > >> >> if i have 1 SSD caching 1 HDD using bcache, the cache mode is writeback > >> >> > >> >> if the PC shutdown/unmount normally, will all dirty data in the cache > >> >> be flushed to backing device before poweroff? > >> > > >> > No, it will remain in the cache. > >> > > >> >> i am afraid that SSD lose data if left without power for a long time. > >> >> e.g. hoilday. > >> > > >> > Wouldn't your data be retained if you used the SSD alone? SSDs should be > >> > stable in a powered off state unless it is a bad device. > >> > > >> > There exist RAM-based disks that may be volatile, but that is unlikely to > >> > be your situation. > >> > > >> > -- > >> > Eric Wheeler > >> > > >> >> > >> >> Thanks in advance, > >> >> C > >> >> -- > >> >> 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] 6+ messages in thread
end of thread, other threads:[~2016-05-11 1:13 UTC | newest] Thread overview: 6+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2016-04-26 9:26 writeback mode behaviour on proper shut down ching lu 2016-04-26 19:57 ` Eric Wheeler 2016-04-27 1:45 ` ching lu 2016-04-27 2:10 ` Eric Wheeler 2016-04-28 3:55 ` ching lu 2016-05-11 1:14 ` Eric Wheeler
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