[Lustre-discuss] Lustre and SSD hard disk

[Andreas Dilger]

On 2010-11-23, at 01:29, Johann Lombardi wrote:
> On Tue, Nov 23, 2010 at 03:12:41PM +0700, sd a wrote:
>> I've just implemented a lustre system which has 4 OSS and 32 SSD hard disk.  But, I got a big problem: lustre doesn't support new kernel. That means, no SSD TRIM command is supported.
> 
> 1.8.5 (should be released soon) will support the SLES11 SP1 kernel (based on 2.6.32) which supports the discard/TRIM commands thanks to the "discard" mount option. However, we have not tested it, so i cannot really tell whether or not it works well with ldiskfs/lustre.

Note that testing of the "discard" mount option (by other ext4 filesystem developers, not related to Lustre) has shown that it can significantly hurt the io performance due to the slowness of the TRIM commands, and the kernel implements TRIM like a barrier so it slows down all of the IO.

Cheers, Andreas
--
Andreas Dilger
Lustre Technical Lead
Oracle Corporation Canada Inc.