> Hi, > > > On Sun, 23 Nov 2008, Amos Jeffries wrote: >> Chris Robertson wrote: >>> Al - Image Hosting Services wrote: >>>> I hope that someone can help me. I have 3 servers running squid acting >>>> as >>>> a web accelerator for a single http server. I have been having a large >>>> amount of problems with the http server locking up and having drive >>>> failures and squid seems to be a great solution. I was pleasantly >>>> surprised at the performance of squid when I first installed it. Even >>>> on >>>> the slowest of my servers, it seemed faster than directly from the >>>> http >>>> server, but after I put the load back on the slowest of my servers it >>>> was >>>> 0% idle. >>> >>> Where is the CPU usage at, User, System or Wait? >>> >>>> Since this server had a second hard drive that was basically not being >>>> used, I moved the squid cache over to it. I then did some googling and >>>> I >>>> made some other changes and the server is now only 0% idle a few times >>>> a >>>> day. I am really suprised at just how tunable squid is and it was >>>> wonderful that a change in configuration could make such a difference. >>>> But >>>> since the busy season is coming, I still think that more can be done >>>> to >>>> tune it. >>>> >>>> Here are the changes that I made to the squid.conf: >>>> redirect_rewrites_host_header off >>>> acl all src 0.0.0.0/0.0.0.0 >>>> acl manager proto cache_object >>>> acl localhost src 127.0.0.1/255.255.255.255 >>>> acl to_localhost dst 127.0.0.0/8 >>>> acl SSL_ports port 443 >>>> acl CONNECT method CONNECT >>>> http_access allow manager localhost >>>> http_access deny manager >>>> http_access deny !Safe_ports >>>> http_access deny CONNECT !SSL_ports >>>> http_access allow all >> >> Not a good idea, limit the access to just the domains you are serving >> where >> at all possible. >> >>>> icp_access allow all >>>> http_port 80 accel vhost >>>> cache_peer 10.10.1.4 parent 80 0 no-query originserver >>>> hierarchy_stoplist cgi-bin ? >>>> cache_mem 16 MB >> >> cache_mem is worth expanding, it lets more objects stay in memory and >> skip >> the disk IO waiting times. >> >>>> maximum_object_size_in_memory 128 KB >>>> memory_replacement_policy heap GDSF >>>> cache_replacement_policy heap GDSF >>>> cache_dir ufs /var/squid/cache 200 16 256 >>>> maximum_object_size 2048 KB >>>> cache_swap_low 90 >>>> cache_swap_high 98 >>>> access_log /var/log/squid/access.log squid >>>> cache_log /var/log/squid/cache.log >>>> cache_store_log /var/log/squid/store.log >> >> dump cache_store_log its a waste of disk IO unless you really need it >> for >> something weird. >> >>>> emulate_httpd_log on >>>> buffered_logs on >>>> acl QUERY urlpath_regex cgi-bin \? >>>> cache deny QUERY >>>> refresh_pattern ^ftp: 1440 20% 10080 >>>> refresh_pattern ^gopher: 1440 0% 1440 >>>> refresh_pattern . 0 20% 4320 >>>> acl apache rep_header Server ^Apache >>>> broken_vary_encoding allow apache >>>> half_closed_clients off >>>> icp_port 0 >>>> log_icp_queries off >>>> coredump_dir /var/squid/cache >>>> >>>> Are there any other changes that can be made to improve cpu usage? >>>> >>>> I also did an install from source, since I am using NetBSD systems I >>>> used >>>> pkgsrc to install it. There are several build options: >>>> >>>> arp-acl >>>> aufs >>>> carp >>>> coss >>>> diskd >>>> icmp >>>> ipf-transparent >>>> pam-helper >>>> pf-transparent >>>> snmp >>>> ssl >>>> unlinkd >>>> >>>> I looked up what some of these are, but I am not sure how they are >>>> used by >>>> squid or if I really need them. My thought is that if I compiled squid >>>> without these options it could improve performance. I wish there was >>>> more >>>> information on running squid on BSD systems (especially recent info) >>>> and >>>> then maybe I could be sure what effect compiling without an option >>>> would >>>> have. For example, I know what pam is, but do I need it? >>> >>> You are not using authentication, so could do without PAM. >>> >>>> I looked up what unlinkd does and I can see it running, but will it >>>> help >>>> cpu usage to use it? >>> >>> Using --enable-truncate "gives a little performance improvement, but >>> may >>> cause problems when used with async I/O. Truncate uses more filesystem >>> inodes than unlink.." asynch I/O refers to diskd, aufs and coss. The >>> only >>> way to see if that will lower your CPU usage is to try, but... >>> >>>> I don't see diskd running as a seperate process, so I don't know that >>>> I am >>>> even using it. >>> >>> Your cache_dir line specifies "ufs". To use diskd, you need to change >>> that >>> line to... >>> >>> cache_dir diskd /var/squid/cache 200 16 256 > > I tried setting it to diskd and then had a problem with it shutting down > after a few minutes. Is there something else that I need to do to before I > put in this change? > It may be the mentioned problems wit the -truncate option, or it may be something to do with diskd itself. Can you get a trace of why diskd helpers are closing, they should stay active for the full lifetime of Squid. closing only on reconfigure and shutdown. Amos
