On 06/02/14 23:35, Chris Murphy wrote:
On Feb 6, 2014, at 7:43 AM, Wade Hampton
<wadehamptoniv(a)gmail.com> wrote:
> - mount using discard (or use the fstrim program periodically)
The discard/TRIM debate can be found in the archives and also on devel@ archives, and on
XFS archives. Not all SSDs perform that well with discard mount option because TRIM is a
non-queued command, therefore for TRIM commands to be issued the drive cache must be
cleared of all other commands and this can actually make things slower. So really it
depends on your workload type, and the SSD you're using. I wouldn't assume you
must have this enabled. Pretty much every source on this has been wrong, notable the crap
resulting from coverage of Ubuntu moving to discard by default.
Ubuntu will be using a cronjob that calls fstrim, not the discard mount option. They found
that the discard option cause a small performance hit.
https://blueprints.launchpad.net/ubuntu/+spec/core-1311-ssd-trimming
Sam