XFS and trim

[Josef Bacik]

On Sat, Mar 30, 2013 at 9:38 PM, Steven Haigh <netwiz at crc.id.au> wrote:
> Hi all,
>
> Firstly, Please CC me into replies as I'm not subscribed to this list.
>
> I'm trying to confirm that Fedora 18 has enabled trim for XFS filesystems. I
> have added discard to the mount options in /etc/fstab - however I do not see
> it when looking at the output of 'mount':
>
> UUID=b95a7b45-d197-45c0-a7d6-c13f930a38b3 /                       xfs
> defaults,discard 0 1
>
> /dev/sda2 on / type xfs (rw,relatime,attr2,inode64,noquota)
>
> fstrim shows that trim is at least enabled, but I am unable to confirm if it
> is done in realtime, or I am required to run fstrim manually.
>
> # fstrim -v /
> /: 48919015424 bytes were trimmed
>
> Can anyone share some insight into this?
>

IIRC you have to rebuild your initrd so it picks up the new fstab
mount options for /, the other options is you should be able to do
mount -o remount,discard /.  Thanks,

Josef