From: Zdenek Kabelac <zkabelac@redhat.com>
To: Raymond Jennings <shentino@gmail.com>
Cc: LVM general discussion and development <linux-lvm@redhat.com>
Subject: Re: [linux-lvm] thin discards
Date: Sun, 21 Jul 2013 12:47:35 +0200 [thread overview]
Message-ID: <51EBBC47.4040508@redhat.com> (raw)
In-Reply-To: <CAGDaZ_r8EzHgvXj3RM+FxJcjT0Hifz+OLGxgsvY8PDH41kNrwg@mail.gmail.com>
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
next prev parent reply other threads:[~2013-07-21 10:47 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
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 [this message]
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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