* [linux-lvm] thin discards @ 2013-07-15 15:32 Raymond Jennings 2013-07-16 10:16 ` Zdenek Kabelac 0 siblings, 1 reply; 11+ messages in thread From: Raymond Jennings @ 2013-07-15 15:32 UTC (permalink / raw) To: linux-lvm [-- Attachment #1: Type: text/plain, Size: 123 bytes --] I tried to run an fstrim on a mounted thin volume, but got FITRIM: operation not supported. Did I screw up or something? [-- Attachment #2: Type: text/html, Size: 170 bytes --] ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [linux-lvm] thin discards 2013-07-15 15:32 [linux-lvm] thin discards Raymond Jennings @ 2013-07-16 10:16 ` Zdenek Kabelac 2013-07-16 11:33 ` Raymond Jennings 0 siblings, 1 reply; 11+ messages in thread From: Zdenek Kabelac @ 2013-07-16 10:16 UTC (permalink / raw) To: LVM general discussion and development; +Cc: Raymond Jennings Dne 15.7.2013 17:32, Raymond Jennings napsal(a): > I tried to run an fstrim on a mounted thin volume, but got FITRIM: operation > not supported. > > Did I screw up or something? Is the pool device capable of TRIM support ? Which version of lvm2 and kernel is in use ? Zdenek ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [linux-lvm] thin discards 2013-07-16 10:16 ` Zdenek Kabelac @ 2013-07-16 11:33 ` Raymond Jennings 2013-07-21 7:10 ` Raymond Jennings 0 siblings, 1 reply; 11+ messages in thread From: Raymond Jennings @ 2013-07-16 11:33 UTC (permalink / raw) To: Zdenek Kabelac; +Cc: LVM general discussion and development [-- Attachment #1: Type: text/plain, Size: 779 bytes --] Gentoo sys-kernel/gentoo-sources-3.10.1 sys-fs/lvm2-2.02.97-r1 I don't know if the pool device is capable of trim support. I do know that the underlying device, a seagate hard drive, does not support discard. However one would think that thin volumes have their own discard handling to deallocate internally, possibly passing a discard down to the underlying block device as needed. On Tue, Jul 16, 2013 at 3:16 AM, Zdenek Kabelac <zkabelac@redhat.com> wrote: > Dne 15.7.2013 17:32, Raymond Jennings napsal(a): > > I tried to run an fstrim on a mounted thin volume, but got FITRIM: >> operation >> not supported. >> >> Did I screw up or something? >> > > > Is the pool device capable of TRIM support ? > > Which version of lvm2 and kernel is in use ? > > > Zdenek > > > [-- Attachment #2: Type: text/html, Size: 1390 bytes --] ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [linux-lvm] thin discards 2013-07-16 11:33 ` Raymond Jennings @ 2013-07-21 7:10 ` Raymond Jennings 2013-07-21 10:47 ` Zdenek Kabelac 0 siblings, 1 reply; 11+ messages in thread From: Raymond Jennings @ 2013-07-21 7:10 UTC (permalink / raw) To: Zdenek Kabelac; +Cc: LVM general discussion and development [-- Attachment #1: Type: text/plain, Size: 1035 bytes --] So can thin volumes support discards independently of the device underneath them? I expected fstrim to free space in the thin pool. On Tue, Jul 16, 2013 at 4:33 AM, Raymond Jennings <shentino@gmail.com>wrote: > Gentoo > > sys-kernel/gentoo-sources-3.10.1 > sys-fs/lvm2-2.02.97-r1 > > I don't know if the pool device is capable of trim support. I do know > that the underlying device, a seagate hard drive, does not support discard. > However one would think that thin volumes have their own discard handling > to deallocate internally, possibly passing a discard down to the underlying > block device as needed. > > > On Tue, Jul 16, 2013 at 3:16 AM, Zdenek Kabelac <zkabelac@redhat.com>wrote: > >> Dne 15.7.2013 17:32, Raymond Jennings napsal(a): >> >> I tried to run an fstrim on a mounted thin volume, but got FITRIM: >>> operation >>> not supported. >>> >>> Did I screw up or something? >>> >> >> >> Is the pool device capable of TRIM support ? >> >> Which version of lvm2 and kernel is in use ? >> >> >> Zdenek >> >> >> > [-- Attachment #2: Type: text/html, Size: 1958 bytes --] ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [linux-lvm] thin discards 2013-07-21 7:10 ` Raymond Jennings @ 2013-07-21 10:47 ` Zdenek Kabelac 2013-07-21 11:01 ` Raymond Jennings 0 siblings, 1 reply; 11+ messages in thread From: Zdenek Kabelac @ 2013-07-21 10:47 UTC (permalink / raw) To: Raymond Jennings; +Cc: LVM general discussion and development Dne 21.7.2013 09:10, Raymond Jennings napsal(a): > So can thin volumes support discards independently of the device underneath them? > > I expected fstrim to free space in the thin pool. Yes - you are expecting it correctly. Ignore is mostly usable in case you do not want to free already provisioned space - which might be in certain cases better for performance. But you need to use recent enough kernels and lvm2 tools - since discards support required kernel updates. Upstream has this: passdown TRIM -> thin-vol -> thin-pool -> PV (if the PV doesn't support discard - you get kernel report error report and it fallbacks to nopassdown behaviour) nopassdown TRIM -> thin-vol -> thin-pool ignore TRIM -> thin-vol Zdenek ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [linux-lvm] thin discards 2013-07-21 10:47 ` Zdenek Kabelac @ 2013-07-21 11:01 ` Raymond Jennings 2013-07-21 19:40 ` Zdenek Kabelac 0 siblings, 1 reply; 11+ messages in thread From: Raymond Jennings @ 2013-07-21 11:01 UTC (permalink / raw) To: Zdenek Kabelac; +Cc: LVM general discussion and development [-- Attachment #1: Type: text/plain, Size: 1006 bytes --] Do snapshots behave the same way as thin volumes wrt discards? On Sun, Jul 21, 2013 at 3:47 AM, Zdenek Kabelac <zkabelac@redhat.com> wrote: > Dne 21.7.2013 09:10, Raymond Jennings napsal(a): > > So can thin volumes support discards independently of the device >> underneath them? >> >> I expected fstrim to free space in the thin pool. >> > > Yes - you are expecting it correctly. > > Ignore is mostly usable in case you do not want to free already > provisioned space - which might be in certain cases better for performance. > > But you need to use recent enough kernels and lvm2 tools - since discards > support required kernel updates. > Kernel: 3.10.1-gento LVM2: 2.02.97 Are these versions recent enough? Upstream has this: > > passdown TRIM -> thin-vol -> thin-pool -> PV > (if the PV doesn't support discard - you get kernel report error report > and it fallbacks to nopassdown behaviour) > > nopassdown TRIM -> thin-vol -> thin-pool > > ignore TRIM -> thin-vol > > > > Zdenek > > [-- Attachment #2: Type: text/html, Size: 1954 bytes --] ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [linux-lvm] thin discards 2013-07-21 11:01 ` Raymond Jennings @ 2013-07-21 19:40 ` Zdenek Kabelac 2013-07-22 9:47 ` Zdenek Kabelac 0 siblings, 1 reply; 11+ messages in thread From: Zdenek Kabelac @ 2013-07-21 19:40 UTC (permalink / raw) To: Raymond Jennings; +Cc: LVM general discussion and development Dne 21.7.2013 13:01, Raymond Jennings napsal(a): > Do snapshots behave the same way as thin volumes wrt discards? > > > On Sun, Jul 21, 2013 at 3:47 AM, Zdenek Kabelac <zkabelac@redhat.com > <mailto:zkabelac@redhat.com>> wrote: > > Dne 21.7.2013 09:10, Raymond Jennings napsal(a): > > So can thin volumes support discards independently of the device > underneath them? > > I expected fstrim to free space in the thin pool. > > > Yes - you are expecting it correctly. > > Ignore is mostly usable in case you do not want to free already > provisioned space - which might be in certain cases better for performance. > > But you need to use recent enough kernels and lvm2 tools - since discards > support required kernel updates. > > > Kernel: 3.10.1-gento > LVM2: 2.02.97 > > Are these versions recent enough? Nope - 2.02.98 has fixes for discards - it's been just introduced in 2.02.97 and had some problems - possible those you can observe. Zdenek ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [linux-lvm] thin discards 2013-07-21 19:40 ` Zdenek Kabelac @ 2013-07-22 9:47 ` Zdenek Kabelac 2013-07-22 10:12 ` Raymond Jennings 0 siblings, 1 reply; 11+ messages in thread From: Zdenek Kabelac @ 2013-07-22 9:47 UTC (permalink / raw) To: LVM general discussion and development; +Cc: Raymond Jennings Dne 21.7.2013 21:40, Zdenek Kabelac napsal(a): > Dne 21.7.2013 13:01, Raymond Jennings napsal(a): >> Do snapshots behave the same way as thin volumes wrt discards? >> Yes, snapshots are just like any other thin volumes. Just a side note - until I think 3.9 kernel there used to be bug, which had wrong ref-counting of shared blocks. Zdenek ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [linux-lvm] thin discards 2013-07-22 9:47 ` Zdenek Kabelac @ 2013-07-22 10:12 ` Raymond Jennings 2013-07-22 10:16 ` Zdenek Kabelac 0 siblings, 1 reply; 11+ messages in thread From: Raymond Jennings @ 2013-07-22 10:12 UTC (permalink / raw) To: Zdenek Kabelac; +Cc: LVM general discussion and development [-- Attachment #1: Type: text/plain, Size: 548 bytes --] I tried to run a fstrim on a mounted snapshot (regular snapshot, not thin snapshot) and got zip. On Mon, Jul 22, 2013 at 2:47 AM, Zdenek Kabelac <zkabelac@redhat.com> wrote: > Dne 21.7.2013 21:40, Zdenek Kabelac napsal(a): > > Dne 21.7.2013 13:01, Raymond Jennings napsal(a): >> >>> Do snapshots behave the same way as thin volumes wrt discards? >>> >>> > Yes, snapshots are just like any other thin volumes. > > Just a side note - until I think 3.9 kernel there used to be > bug, which had wrong ref-counting of shared blocks. > > Zdenek > > [-- Attachment #2: Type: text/html, Size: 1205 bytes --] ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [linux-lvm] thin discards 2013-07-22 10:12 ` Raymond Jennings @ 2013-07-22 10:16 ` Zdenek Kabelac 2013-07-24 3:12 ` Raymond Jennings 0 siblings, 1 reply; 11+ messages in thread From: Zdenek Kabelac @ 2013-07-22 10:16 UTC (permalink / raw) To: Raymond Jennings; +Cc: LVM general discussion and development Dne 22.7.2013 12:12, Raymond Jennings napsal(a): > I tried to run a fstrim on a mounted snapshot (regular snapshot, not thin > snapshot) and got zip. > I've been talking about thin snapshots. Of course - for old non-thin snapshot - TRIM is not supported. (And it doesn't look like anything simple to implement) Zdenek > > > On Mon, Jul 22, 2013 at 2:47 AM, Zdenek Kabelac <zkabelac@redhat.com > <mailto:zkabelac@redhat.com>> wrote: > > Dne 21.7.2013 21:40, Zdenek Kabelac napsal(a): > > Dne 21.7.2013 13:01, Raymond Jennings napsal(a): > > Do snapshots behave the same way as thin volumes wrt discards? > > > Yes, snapshots are just like any other thin volumes. > > Just a side note - until I think 3.9 kernel there used to be > bug, which had wrong ref-counting of shared blocks. > > Zdenek > > ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [linux-lvm] thin discards 2013-07-22 10:16 ` Zdenek Kabelac @ 2013-07-24 3:12 ` Raymond Jennings 0 siblings, 0 replies; 11+ messages in thread From: Raymond Jennings @ 2013-07-24 3:12 UTC (permalink / raw) To: Zdenek Kabelac; +Cc: LVM general discussion and development [-- Attachment #1: Type: text/plain, Size: 1379 bytes --] As a pure matter of opinion, I enjoy "fat provisioning" on my filesystems, since I run a desktop and in theory it really cuts down on physical fragmentation. Snapshots are something I use whenever I need to make a fundamental reconfiguration to the system as a whole that can't be done live, such as resizing or reconfiguring the root filesystem. This would preclude the unquestionable usage of thin volumes. On Mon, Jul 22, 2013 at 3:16 AM, Zdenek Kabelac <zkabelac@redhat.com> wrote: > Dne 22.7.2013 12:12, Raymond Jennings napsal(a): > > I tried to run a fstrim on a mounted snapshot (regular snapshot, not thin >> snapshot) and got zip. >> >> > I've been talking about thin snapshots. > > Of course - for old non-thin snapshot - TRIM is not supported. > (And it doesn't look like anything simple to implement) > > Zdenek > > > >> >> On Mon, Jul 22, 2013 at 2:47 AM, Zdenek Kabelac <zkabelac@redhat.com >> <mailto:zkabelac@redhat.com>> wrote: >> >> Dne 21.7.2013 21:40, Zdenek Kabelac napsal(a): >> >> Dne 21.7.2013 13:01, Raymond Jennings napsal(a): >> >> Do snapshots behave the same way as thin volumes wrt discards? >> >> >> Yes, snapshots are just like any other thin volumes. >> >> Just a side note - until I think 3.9 kernel there used to be >> bug, which had wrong ref-counting of shared blocks. >> >> Zdenek >> >> >> > [-- Attachment #2: Type: text/html, Size: 2370 bytes --] ^ permalink raw reply [flat|nested] 11+ messages in thread
end of thread, other threads:[~2013-07-24 3:12 UTC | newest] Thread overview: 11+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2013-07-15 15:32 [linux-lvm] thin discards Raymond Jennings 2013-07-16 10:16 ` Zdenek Kabelac 2013-07-16 11:33 ` Raymond Jennings 2013-07-21 7:10 ` Raymond Jennings 2013-07-21 10:47 ` Zdenek Kabelac 2013-07-21 11:01 ` Raymond Jennings 2013-07-21 19:40 ` Zdenek Kabelac 2013-07-22 9:47 ` Zdenek Kabelac 2013-07-22 10:12 ` Raymond Jennings 2013-07-22 10:16 ` Zdenek Kabelac 2013-07-24 3:12 ` Raymond Jennings
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