[linux-lvm] strange usage stats for thin LV

[Lukáš Czerner]

On Thu, 8 Nov 2012, Andres Toomsalu wrote:

> Date: Thu, 8 Nov 2012 00:03:15 +0200
> From: Andres Toomsalu <andres at active.ee>
> Reply-To: LVM general discussion and development <linux-lvm at redhat.com>
> To: LVM general discussion and development <linux-lvm at redhat.com>
> Subject: Re: [linux-lvm] strange usage stats for thin LV
> 
> Apparently that does not work - FITRIM ioctl not backported to RHEL6 kernel perhaps?
> 
> fstrim -v /backup
> fstrim: /backup: FITRIM ioctl failed: Operation not supported
> 
> df -h
> /dev/mapper/VolGroupL0-thin_backup 591G  104G  458G  19% /backup
> 
> mount (added discard option today)
> /dev/mapper/VolGroupL0-thin_backup on /backup type ext4 (rw,discard)
> 
> Cheers,

Hi,

can you please check if the device *really* support discard ? What
is the output of

grep . /sys/block/<device>/queue/discard_*


<device> is whatever /dev/mapper/VolGroupL0-thin_backup is pointing
to.

Thanks!
-Lukas