Re: [squid-users] Performance Extremely squid configuration advice

and now which filesystem has better performance. aufs or diskd? on the
SAS hdd for example.

On Fri, Jan 7, 2011 at 7:56 PM, Drunkard Zhang <gongfan193_at_gmail.com> wrote:
>
> 2011/1/7 Amos Jeffries <squid3_at_treenet.co.nz>:
> > On 07/01/11 19:08, Drunkard Zhang wrote:
> >>
> >> In order to get squid server 400M+ traffic, I did these:
> >> 1. Memory only
> >> IO bottleneck is too hard to avoid at high traffic, so I did not use
> >> harddisk, use only memory for HTTP cache. 32GB or 64GB memory per box
> >> works good.
> >
> > NP: The problem in squid-2 is large objects in memory. Though the more
> > objects you have cached the slower the index lookups (very, very minor
> > impact).
> >
>
> With 6-8GB memory, there's about 320K objects per instance, so no
> significant delay would yield.
>
> >>
> >> 2. Disable useless acl
> >> I did not use any acl, even default acls:
> >> acl SSL_ports port 443
> >> acl Safe_ports port 80          # http
> >> acl Safe_ports port 21          # ftp
> >> acl Safe_ports port 443         # https
> >> acl Safe_ports port 70          # gopher
> >> acl Safe_ports port 210         # wais
> >> acl Safe_ports port 1025-65535  # unregistered ports
> >> acl Safe_ports port 280         # http-mgmt
> >> acl Safe_ports port 488         # gss-http
> >> acl Safe_ports port 591         # filemaker
> >> acl Safe_ports port 777         # multiling http
> >> acl Safe_ports port 901         # SWAT
> >> http_access deny !Safe_ports
> >> http_access deny CONNECT !SSL_ports
> >>
> >> squid itself do not do any acls, security is ensured by other layers,
> >> like iptables or acls on routers.
> >
> > Having the routers etc assemble the packets and parse the HTTP-layer
> > protocol to find these details may be a larger bottleneck than testing for
> > them inside Squid where the parsing has to be done a second time anyway to
> > pass the request on.
> >
>
> We only do http cache on tcp port 80, and the incoming source IPs is
> controllable, so iptables should be OK.
>
> > Note that the default port and method ACL in Squid are validating on the
> > HTTP header content URLs not the packet destination port.
> >
> >>
> >> 3. refresh_pattern, mainly cache for pictures
> >> Make squid cache as long as it can, so it looks likes this:
> >> refresh_pattern -i \.(jpg|jpeg|gif|png|swf|htm|html|bmp)(\?.*)?$
> >> 21600 100% 21600  reload-into-ims ignore-reload ignore-no-cache
> >> ignore-auth ignore-private
> >>
> >> 4. multi-instance
> >> I can't get single squid process runs over 200M, so multi-instance
> >> make perfect sense.
> >
> > Congratulations, most can't get Squid to go over 50MBps per instance.
> >
> >> Both CARP frontend and backend (for store HTTP files) need to be
> >> multi-instanced. Frontend configuration is here:
> >> http://wiki.squid-cache.org/ConfigExamples/ExtremeCarpFrontend
> >>
> >> I heard that squid is still can't process "huge" memory properly, so I
> >> splited big memory into 6-8GB per instance, which listens at ports
> >> lower than 80. And on a box with 32GB memory CARP frontend configs
> >> like this:
> >>
> >> cache_peer 192.168.1.73 parent 76 0 carp name=73-76 proxy-only
> >> cache_peer 192.168.1.73 parent 77 0 carp name=73-77 proxy-only
> >> cache_peer 192.168.1.73 parent 78 0 carp name=73-78 proxy-only
> >> cache_peer 192.168.1.73 parent 79 0 carp name=73-79 proxy-only
> >>
> >> 5. CARP frontend - cache_mem 0 MB
> >> I used to use "cache_mem 0 MB", time flies, I think that files smaller
> >> than 1.5KB would be waste if GET from CARP backend, am I right? I use
> >> these now:
> >>
> >> cache_mem 5 MB
> >> maximum_object_size_in_memory 1.5 KB
> >
> > The best value here differs on every network so we can't answer your
> > question with details.
>
> Here's my idea: did 3 times of tcp hand shake, and transfered data in
> ONE packet is silly, so let it store locally. According to my
> observation, no more than 500 StoreEntries per CARP frontend.
>
> > Log analysis of live traffic will show you the amount of objects your Squid
> > are handling in each size bracket. That will determine where the best place
> > to set this limit at to reduce the lag on small items versus your available
> > cache_mem memory.
> >

--
Seyyed Mohsen Saeedi
سید محسن سعیدی