checkums when converting from ext[234] to Btrfs

checkums when converting from ext[234] to Btrfs

[pubny]

Hi,

Could someone help me with a clarification whether the btrfs-convert
tool creates checksums on blocks of the existing ext[234] filesystem?

Any experiences how the size and the filesystem utilization (used vs.
total diskspace) impacts the time of conversion?

Thanks,
G=C3=A1bor



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Re: checkums when converting from ext[234] to Btrfs

[David Sterba]

On Wed, Jan 04, 2012 at 03:22:11PM +0100, pubny wrote:
> Could someone help me with a clarification whether the btrfs-convert
> tool creates checksums on blocks of the existing ext[234] filesystem?

yes, it does checksum by default and you can switch it off with the '-d'
option.

> Any experiences how the size and the filesystem utilization (used vs.
> total diskspace) impacts the time of conversion?

I don't have numbers but it needs to go through extX metadata, read and
checksum data blocks, then write btrfs metadata. Nothing where a
significant time could be saved (except switching off the checksums).


david

Re: checkums when converting from ext[234] to Btrfs

[pubny]

Thanks David. That's very helpful.

Regards,
G=C3=A1bor


-----Original Message-----
=46rom: David Sterba <dave@jikos.cz>
Reply-to: dave@jikos.cz
To: pubny <pubny@xs4all.nl>
Cc: linux-btrfs@vger.kernel.org
Subject: Re: checkums when converting from ext[234] to Btrfs
Date: Thu, 5 Jan 2012 16:45:41 +0100
Mailer: Mutt/1.4.2.2i

On Wed, Jan 04, 2012 at 03:22:11PM +0100, pubny wrote:
> Could someone help me with a clarification whether the btrfs-convert
> tool creates checksums on blocks of the existing ext[234] filesystem?

yes, it does checksum by default and you can switch it off with the '-d=
'
option.

> Any experiences how the size and the filesystem utilization (used vs.
> total diskspace) impacts the time of conversion?

I don't have numbers but it needs to go through extX metadata, read and
checksum data blocks, then write btrfs metadata. Nothing where a
significant time could be saved (except switching off the checksums).


david

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