Re: TRIM support with XFS
On 7/5/2013 2:07 AM, John Andreasson wrote:
> On Mon, Jul 1, 2013 at 12:05 AM, Stan Hoeppner <stan@hardwarefreak.com> wrote:
>> Hmm...
>>
>> Last thing to try is rootflags. To your kernel line in menu.lst add
>>
>> root=/dev/sdXX rootflags=discard ro
>
> Thanks. I tried that as well but it still doesn't work.
>
> Just to be sure I created a file with random data, read the sectors
> with hdparm and then removed the file and did a flush. If discard was
> active the sector should be zeroed out. It was however still there
> after a sync, and also after waiting an hour just in case.
>
>> If that doesn't do it maybe there's a bug here.
>
> It sounds like that.
>
> I took a look at the xfs source code in the kernel tree. It looks like
> the discard code is simply never called except for when there's an
> ioctl call. I guess that's what fstrim triggers. But from what I could
> see there's no realtime support in kernel right now. I guess I should
> go with ext4 for now.
Ask on the XFS mailing list. I'm pretty sure some of the XFS devs use
XFS as rootfs w/Debian on SSD (Dave Chinner IIRC). According to
Christoph discard should work with any kernel above 3.0--Wheezy is
3.2--as long as the other requirements are met. And your system seems
to meet the others.
--
Stan
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