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From: "Bryn M. Reeves" <bmr@redhat.com>
To: LVM general discussion and development <linux-lvm@redhat.com>
Subject: [linux-lvm] lvm2: zeroing free space
Date: Fri, 04 Feb 2011 14:12:03 +0000	[thread overview]
Message-ID: <4D4C0933.80107@redhat.com> (raw)

Hi Folks,

Recently had a query from someone using an array supporting thin provisioning
with zero page reclaim[1].

They wanted a method to write zeros to all the unallocated space in a VG to
trigger a reclaim of unused regions in the VG's PVs.

My suggestion was to lvcreate a -l100%FREE LV named "filler" and overwrite it
from /dev/zero.

It seems like this might something a lot of users want as this functionality
gets to be more common.

I wondered if it could be worth adding a script to automate this or even an
option to vgchange (e.g. --zero-free-space)?

Didn't have time to try putting anything together yet but it seems such a
feature could be useful.

Regards,
Bryn.

[1] http://blogs.hds.com/hu/2009/03/zero-page-reclaim.html

             reply	other threads:[~2011-02-04 14:12 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-02-04 14:12 Bryn M. Reeves [this message]
2011-02-04 15:54 ` [linux-lvm] lvm2: zeroing free space Mike Snitzer
2011-02-04 16:21   ` hansbkk
2011-02-04 16:37   ` Bryn M. Reeves
2011-02-04 20:02     ` Martin K. Petersen
2011-02-08  2:10     ` wayne.berthiaume

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