Re: [squid-users] RE: Increased service times using aufs vs diskd

O'Brien, Kevin wrote:
> No takers?
>
> The other interesting thing is that the service times increase as
> traffic decreases. Any theories on that?
>
> -=Kevin=-
>
> _____________________________________________
> Sent: Thursday, June 22, 2006 1:22 PM
> To: 'squid-users@squid-cache.org'
> Subject: Increased service times using aufs vs diskd
>
> I'm using squid as an accelerator and I switched my cache_dir from diskd
> (used because server is SMP) to aufs because of various bugs in the
> diskd code (761, 1500). However, when I make the switch (and clear the
> cache_dir contents) the overall, hit, miss, and near miss service times
> increase by almost 10 times. Using diskd, the 24 hour average for
> overall, hit, and near miss is 4ms and near miss is 1ms. After the
> switch, the times rocket up to 44ms, 43ms, 49ms, and 45ms for overall,
> hit, miss, and near miss. I am wondering if this is just a function of
> the squid process now handling disk requests or is an indication of
> another problem (although ~40ms is probably not much of a problem).
>
> Here's the details of the system:
> OS: RHEL4
> Squid: 2.5.stable14 with epoll patch
> Build options: ./configure --enable-epoll --enable-snmp
> --enable-removal-policies=heap,lru --enable-storeio=aufs,diskd,ufs
> --with-pthreads --enable-cachemgr-hostname=localhost
> --disable-ident-lookups --enable-truncate --enable-cache-digests
> --enable-htcp
>

<snip>

I didn't see what filesystem you are using. Changing from ext3 to ext2
and setting noatime on the cache_dir disks helped us in this circumstance.

-- 
Mike Rambo
mrambo@lsd.k12.mi.us
Many today claim to be tolerant. True tolerance, however, can cope
with others being intolerant.
     -Nigel Cunningham