Re: [exim] FreeBSD ffs vs. ufs?

On 2006-07-17 at 14:00 +1000, Marcus Barczak wrote:
> I'm currently doing some performance tuning on a pretty heavily used
> exim server we have here. We're running FreeBSD 6.1 and am noticing
> the disk loading to be quite high. The filesystems are currently
> configured as UFS however i'm contemplating using tunefs to switch
> them to FFS with soft updates enabled.

If you're using anti-virus integration then the load on the filesystems
can be quite high. If there's too much activity then the FS can't keep
up and can get confused, leading to the FS having content (as seen via
df) but not linked in (seen via du) and with no processes having open
file-descriptors (seen via lsof).

If this happens, you can't unmount the FS and end up needing to reboot
(during which the syncer process will time out trying to write blocks)
and "fsck -p" on reboot.

After that, you'll have your disk space back.

The softupdates issues under sustained high load are known to be an
issue, you should be able to find references to them with enough
searching. Of course, without softupdates you have performance issues,
so it's a matter of choosing which causes you the least pain.
--
"Everything has three factors: politics, money, and the right way to do it.
In that order." -- Gary Donahue