Re: [squid-users] Squid 2.6-STABLE6 100% cpu load, lots of iowait and coredumps

Jason Taylor wrote:
> We recently upgraded our extremely old squid servers (P3-1GHz, 512MB
> ram) to modern hardware (3GHz P4, 2GB ram) running RedHat linux. The
> problem I am experiencing is that CPU load will jump to 100% and stay
> there. The system shows about 50% iowait cpu usage. We have about
> 1500 employees using two such machines. Also, squid seems to dump
> core and restart several times during all this. My coredump_dir
> directory has many core files in it, about 10 or 11 per day when the
> load-spike happens. Some days, things are just fine.
>
> I haven't had much time to validate all of this as I am just back from
> my holiday and this is what I see on the systems for now. At the
> moment, the machines are playing nice, likely because the bulk of
> user-load has been switched back to the old proxies for the time being.
>
> Disk-wise, the servers each have two 146GB scsi disks in a hardware
> mirror with all space (except /boot and swap) allocated to "/". Not
> ideal, but I am not the one responsible for the hardware config. The
> filesystem is ext3.
>
> Here is the output of df -k:
> Filesystem 1K-blocks Used Available Use% Mounted on
> /dev/sda3 139707024 16431300 116179012 13% /
> /dev/sda1 256666 16053 227361 7% /boot
> none 1037388 0 1037388 0% /dev/shm
>
> Here is the output of uname -a:
> Linux spco1pxya 2.6.9-34.ELsmp #1 SMP Fri Feb 24 16:54:53 EST 2006
> i686 i686 i386 GNU/Linux
>
> Here is how squid-2.6-STABLE6 was built:
> ./configure \
> --enable-delay-pools \
> --enable-useragent-log \
> --enable-referer-log \
> --disable-wccp \
> --enable-err-languages="English French" \
> --enable-linux-netfilter \
> --disable-ident-lookups \
> --enable-auth="basic digest ntlm" \
> --enable-basic-auth-helpers="getpwnam LDAP MSNT multi-domain-NTLM
> NCSA SASL SMB" \
> --enable-ntlm-auth-helpers="fakeauth no_check
> SMB" \
> --enable-digest-auth-helpers="ldap
> password" \
> --enable-external-acl-helpers="ip_user ldap_group session unix_group
> wbinfo_group" \
> --with-large-files
>
> Here is the excerpt from the squid-conf pertaining to cache-size:
> cache_dir ufs /var/squid/cache 2048 16 256

I'd advise using aufs, as it's non-blocking. This will require a
recompile, with either --enable-async-io or --enable-storeio="ufs,
aufs". Another great CPU hog is the regex ACLs. Avoid them whenever
possible.

Even so, Squid shouldn't be crashing.

>
>
> What configurations can I do to my OS and squid in order to get rid of
> this bottleneck?
>
>
> Cheers,
>
> /Jason

Chris
Received on Fri Jan 12 2007 - 16:45:24 MST