Re: [squid-users] Fastest accelerator setup I could come up with

Markus Meyer wrote:
> Hi all,
>
> after I tortured this list for hints on tuning Squid in an accelerator
> set up I did some testing and now like to share what came out of it. The
> following proved to be the most reliable and fasted set up. Also it goes
> easy on the resources.
> I haven't done any benchmarking so I can't give you maximum numbers.

Can you grab some ball-park figures as described
http://wiki.squid-cache.org/KnowledgeBase/Benchmarks ?

> Since we use two siblings in our production environment I was able to
> compare directly any changes with our old set up by tuning only one of
> the two siblings and leaving the other as it was.
> I was able to lower most of the performance indicators like CPU, I/O by
> 30 - 40% with the below set up.
> If you have any questions please feel free to ask. I'm sure I forgot
> something here.
>
> First our content. We serve only pictures, lots of them. Here is the
> read histogram as the cachemgr shows it:
> 1- 1: 947 0%
> 2- 2: 880 0%
> 3- 4: 1705 0%
> 5- 8: 2964 0%
> 9- 16: 5238 0%
> 17- 32: 13366 0%
> 33- 64: 25554 0%
> 65- 128: 49637 0%
> 129- 256: 958687 1%
> 257- 512: 26930299 38%
> 513- 1024: 1094073 2%
> 1025- 2048: 14418961 20%
> 2049- 4096: 19701586 28%
> 4097- 8192: 3839852 5%
> 8193-16384: 2841771 4%
> 16385-32768: 791308 1%
>
> As you can see we have to handle mostly very, very small files which is
> a real pain in the a**. So COSS was my white knight to handle this.
>
> Although we don't use CARP we made sure that the proxies always get the
> same requests. We have at our prime time about 40 MBit/s outgoing
> traffic which makes about 1000 requests per second.
> Also I should mention that we use a standard Debian kernel with no
> tuning in any kernel parameters except the following two:
> net.ipv4.tcp_max_syn_backlog = 4096
> vm.swappiness = 0
>
> Now some numbers...
>
> Hardware
> ======
> CPU: Intel Xeon 2GHz (dual quad-core)
> RAM: 16 GB
> Disk: 4x 136 GB
>
> Configuration
> =========
> Squid can use the maximum number of file descriptors: 65536
> I left out the ACLs we use and stuff like purging and cachemgr access.
> Any configuration items not mentioned here have their default values.
> All new options I mark with '->' at the beginning of the line:
>
> # disable all the proxy networking stuff, we are standalone
> htcp_port 0
> announce_port 0
> icp_port 0
>
> # we are a accelerator so listen on standard http port
> # IP is that of img5
> http_port 80 accel vport defaultsite=img5
>
> # define the backend servers and balance between them
> cache_peer ws1 parent 80 0 no-query no-digest originserver round-robin
> name=s1
> cache_peer ws2 parent 80 0 no-query no-digest originserver round-robin
> name=s2
> # our sibling for Cache Digest exchange
> cache_peer wi10 sibling 80 0 proxy-only name=i10
> # this comes from ICP times and I'm not sure if it's still needed with
> Cache Digest
> acl sibling10 src i10
> miss_access deny sibling10
>
> # lowers the response time dramatically
> #
> http://wiki.squid-cache.org/Features/CollapsedForwarding?highlight=(collapsed)
> collapsed_forwarding on
>
> # we have 16GB and use 4 as cache. This is a good trade-off between FS cache
> # and Squids memory usage.
> -> cache_mem 4096 MB
>
> ### Replacement policies
> # mem - Heap GSDF: fast and small objects preferred. Better to have more
> # small objects in memory than to read them from disk.
> -> memory_replacement_policy heap GDSF
> # disk - Heap LFUDA: fast and more popular pictures, more "hot" content,
> # is preferred.
> -> cache_replacement_policy heap LFUDA
>
> # This seems to help speed up things too.
> -> quick_abort_min 0 KB
> -> quick_abort_max 0 KB
> -> quick_abort_pct 100
>
> # we don't need detailed client information
> -> client_db off
>
> # close connections fast
> -> half_closed_clients off
>
> ### Cache directories
> # COSS stuff, ca. 16 GB in size, maximum file size is 24kB
> -> cache_dir coss /web/cache/1/coss 16373 max-size=24576 block-size=1024
> -> cache_dir coss /web/cache/2/coss 16373 max-size=24576 block-size=1024
> -> cache_dir coss /web/cache/3/coss 16373 max-size=24576 block-size=1024
> -> cache_dir coss /web/cache/4/coss 16373 max-size=24576 block-size=1024
> # using async-io on ca. 60 GB
> cache_dir aufs /web/cache/1/aufs 61440 290 256 min-size=24576
> cache_dir aufs /web/cache/2/aufs 61440 290 256 min-size=24576
> cache_dir aufs /web/cache/3/aufs 61440 290 256 min-size=24576
> cache_dir aufs /web/cache/4/aufs 61440 290 256 min-size=24576
>
> # since our content changes very fast we rebuild the digest every ten
> minutes
> digest_rebuild_period 10 minutes
> digest_rewrite_period 10 minutes
>
> # don't send the version string
> httpd_suppress_version_string on
>
> ## LOGGGING STUFF
> # don't need the store log
> cache_store_log none
> # define access.log
> #access_log /var/log/squid/access.log
>
> ### INCLUDES
> include /etc/squid/conf.d/*.conf
>

Anything tuning-related in /etc/squid/conf.d/*.conf ?

Thank you very, very much. This will be a big help. I assume since you
made this public it's also fine to add this to the wiki?

Amos

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