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From: Alasdair G Kergon <>
To: Scott Moser <>
Subject: Re: [linux-lvm] Why does thinpool take 2*poolmetadatasize space?
Date: Tue, 20 Oct 2020 18:02:52 +0100	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

On Tue, Oct 20, 2020 at 12:33:41PM -0400, Scott Moser wrote:
> When I create an lvmthinpool with size S and poolmetadatasize P,
> it reduces the available freespace by S+2P. I expected that to
> be S+P. Where did the extra poolmetadatasize get used?

So that you have sufficient disk space to store a second copy of it
if you need to perform any work on the metadata in future.

Recovery operations, for example, create a recovered copy in that
'spare' space then swap to use it leaving the space used by the
original metadata as the new 'spare'.


  reply	other threads:[~2020-10-20 17:02 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-20 16:33 Scott Moser
2020-10-20 17:02 ` Alasdair G Kergon [this message]
2020-10-20 18:02 ` Zdenek Kabelac

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