I run 2.6 STABLE19. We are dealing with many issues related to queue congenstion, I/O, slowness over time...etc. My thoughts are that its how we have the disks setup and possibly OS/Squid configuration. Anyways, as a test I want to disable the ability for squid to use the cache for anything...no writing to it, no reading from it. The squid server is just one big raid5 of 4 disks (part of my concern), 15krpm each
I've found many posts about how to use an acl to define dstdomains , also the cache deny ACL_name ...etc. I have store.log reenabled and I still see activity in my cache for certain dstdomains I have set to "cache deny"
How can I properly disable caching and then verify it.
Some squid.conf directives:
cache_mem 8 MB
cache_dir aufs /usr/local/squid/var/cache 9999 16 256
Squid Cache: Version 2.6.STABLE19
configure options: '--enable-auth=ntlm,basic' '--enable-external-acl-helpers=wbinfo_group' '--enable-delay-pools' '--enable-snmp' '--enable-storeio=aufs' '--enable-smartfilter'
I am fighting with squid randomly causing all people using it to experience very slow access through it. Restarting the squid process usually fixes it for a bit.
Some concerns:
squidaio_queue_request: WARNING - Queue congestion
httpReadReply: Excess data from (prob unrelated)
pstree:
├─squid───squid─┬─130*[sf_userinfo]
│ ├─unlinkd
│ └─19*[{squid}]
Here is some iostat output over 30 sec:
iostat -x -d 5
Linux 2.6.18-53.el5PAE (server_name) 09/25/2008
Device: rrqm/s wrqm/s r/s w/s rsec/s wsec/s avgrq-sz avgqu-sz await svctm %util
cciss/c0d0 1.10 57.96 5.79 27.45 178.31 683.04 25.91 1.10 33.19 3.96 13.18
dm-0 0.00 0.00 6.56 85.36 177.57 682.87 9.36 2.81 30.52 1.43 13.14
dm-1 0.00 0.00 0.01 0.00 0.07 0.00 8.00 0.00 3.94 0.26 0.00
Device: rrqm/s wrqm/s r/s w/s rsec/s wsec/s avgrq-sz avgqu-sz await svctm %util
cciss/c0d0 0.00 34.20 0.00 12.20 0.00 367.60 30.13 0.21 17.57 6.11 7.46
dm-0 0.00 0.00 0.00 45.80 0.00 366.40 8.00 0.71 15.45 1.55 7.12
dm-1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
Device: rrqm/s wrqm/s r/s w/s rsec/s wsec/s avgrq-sz avgqu-sz await svctm %util
cciss/c0d0 0.00 39.20 0.00 13.60 0.00 422.40 31.06 0.24 17.29 5.31 7.22
dm-0 0.00 0.00 0.00 52.80 0.00 422.40 8.00 0.82 15.45 1.37 7.24
dm-1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
Device: rrqm/s wrqm/s r/s w/s rsec/s wsec/s avgrq-sz avgqu-sz await svctm %util
cciss/c0d0 0.00 77.20 0.00 21.40 0.00 788.80 36.86 0.23 10.64 4.64 9.94
dm-0 0.00 0.00 0.00 98.60 0.00 788.80 8.00 1.10 11.17 1.01 9.94
dm-1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
Device: rrqm/s wrqm/s r/s w/s rsec/s wsec/s avgrq-sz avgqu-sz await svctm %util
cciss/c0d0 0.00 45.40 0.00 14.60 0.00 480.00 32.88 0.34 23.60 5.58 8.14
dm-0 0.00 0.00 0.00 60.00 0.00 480.00 8.00 1.15 19.16 1.36 8.14
dm-1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
Device: rrqm/s wrqm/s r/s w/s rsec/s wsec/s avgrq-sz avgqu-sz await svctm %util
cciss/c0d0 0.00 74.00 0.00 33.80 0.00 862.40 25.51 0.79 23.24 4.64 15.70
dm-0 0.00 0.00 0.00 107.80 0.00 862.40 8.00 2.05 19.02 1.46 15.70
dm-1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
