[linux-lvm] thin discards
zkabelac at redhat.com
Sun Jul 21 10:47:35 UTC 2013
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
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