On 13/05/13 11:23, David Boreham wrote:
> btw we deploy on CentOS6. The only things we change from the default are:
>
> 1. add "relatime,discard" options to the mount (check whether the most
> recent CentOS6 does this itself -- it didn't back when we first deployed
> on 6.0).
While it is important to let the SSD know about space that can be
reclaimed, I gather the operation does not perform well.
I *think* current advice is to leave 'discard' off the mount options,
and instead run a nightly cron job to call 'fstrim' on the mount point
instead. (In really high write situations, you'd be looking at calling
that every hour instead I suppose)
I have to admit to have just gone with the advice, rather than
benchmarking it thoroughly.
tjc