[OpenAFS] Re: Fstab options for AFS on SSDs

Andrew Deason adeason@sinenomine.net
Thu, 1 Aug 2013 12:17:51 -0500

On Thu, 01 Aug 2013 18:40:14 +0200
Jaap Winius <jwinius@umrk.nl> wrote:

> Recently I've started using SSDs in both servers and workstations and  
> this article -- https://wiki.debian.org/SSDOptimization -- offers some  
> suggestions on which options to use in /etc/fstab, e.g.  
> "discard,noatime,commit=600,defaults" for /boot. But would it be okay  
> to use these options for /vicepX and AFS cache partitions as well?

Short answer: yes.

'noatime' is definitely fine for /vicepX partitions, since we don't look
at file atime for anything. For a cache partition, I think we do look at
the atime for cache files on startup to estimate which chunks were most
recently accessed, but I don't think that's terribly important. You'd
probably get much more of a performance benefit from turning on noatime
than you would from more accurate timestamps on startup. 

'discard' and 'commit=600' I don't think are very relevant to AFS, or in
general to which application you're running on top of the filesystem.
'discard' I've heard may help or hurt performance depending on usage
patterns (look at running 'fstrim' as an alternative). And 'commit=600'
means you may lose data up to 10 minutes ago if you crash or lose power
(unless you fiddle with the -sync option for servers). So, they have
upsides and downsides, but I don't think any of that changes whether
you're talking about AFS or anything else.

Andrew Deason