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From: Zdenek Kabelac <>
To: LVM general discussion and development <>,
	Douglas Paul <>
Subject: Re: [linux-lvm] Unable to un-cache logical volume when chunk size is over 1MiB
Date: Mon, 21 Jan 2019 21:19:52 +0100	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

Dne 18. 07. 18 v 16:58 Douglas Paul napsal(a):
> On Wed, Jul 18, 2018 at 03:25:10PM +0100, Ryan Launchbury wrote:
>> Does anyone have any other ideas or potential workarounds for this issue?
>> Please let me know if you require more info.
> I didn't see this in the previous messages, but have you tried temporarily
> remounting the filesystems read-only if you can't unmount them?
> Also, earlier you mentioned looking at /var/log/dmesg for write errors.  On
> my systems, that only contains a snapshot at boot. I have to run dmesg to
> see the latest updates. It seems suspicious to have nothing in the dmesg
> during 61 days past 10 seconds after system boot ...


So this should help:

lvchange --cachesettings  migration_threshold=16384 vg/cacheLV

the problem was the usage of unexpectedly big chunk sizes,
that are used when cache-pool size is big (>TiB) and chunksizes
are  >= 1MiB.

Upstream has committed patches for automatic protection against too small
migration threshold.


      reply	other threads:[~2019-01-21 20:19 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-06-20  9:18 [linux-lvm] Unable to un-cache logical volume when chunk size is over 1MiB Ryan Launchbury
2018-06-20 10:15 ` Zdenek Kabelac
2018-06-20 11:10   ` Ryan Launchbury
2018-06-22 18:13   ` Gionatan Danti
2018-06-22 19:22     ` Ryan Launchbury
2018-06-22 20:07     ` Zdenek Kabelac
2018-06-23 10:09       ` Gionatan Danti
2018-06-24 19:18         ` Ryan Launchbury
2018-06-25 17:19           ` Gionatan Danti
2018-06-25 17:20             ` Ryan Launchbury
2018-06-25 17:40               ` Gionatan Danti
2018-07-18 14:25                 ` Ryan Launchbury
2018-07-18 14:58                   ` Douglas Paul
2019-01-21 20:19                     ` Zdenek Kabelac [this message]

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