From: "Adam Aube" <aaube01@xxxxxxxxx> Sent: Thursday, January 20, 2005 1:46 PM Subject: [squid-users] Re: Help me About Squid Oliver Hookins wrote: Umar Draz wrote: I have 512MB ram and 1100MB swap now questions is this i have set 5GB /cache so what should be cache_mem If you check out the archives you will see that the rule of thumb for disk cache to memory cache is about 100:1 (if I remember correctly). So for a 5GB disk cache you should have 50MB of memory to handle it. No, that's the rule of thumb for how much memory Squid will use to store cache metadata, which is based purely on the size of the cache. The cache_mem setting controls how much memory Squid will use to cache on-disk objects in memory (which improves performance). Generally the default for cache_mem does not need to be changed, because the OS itself will use free memory to cache files. Items in Squid's cache that are frequently or recently accessed will be included in this file cache. If a memory shortage occurs, the OS can dump file cache to free up memory, but memory used by Squid's cache_mem setting can only be recovered by swapping out Squid, which will drastically hurt performance. Adam Following the thread above, I have 4Gb RAM, 11Gb for the cache and 5Gb for swap. I've set cache_mem to 2Gb as I too thought that the higher this field was set to, the better the performance would be, as Squid would be able to store more in memory, therfore requiring less retrievals from the disk. Users are complaining about internet speed and I have been blaming WAN bandwidth from their location up to the Squid servers and also the ISP link. I'm now a bit worried that I've misinterpreted previous mailings on sizing of cache_mem. Can you clarify, as my swap is currently using 1Gb as well as all the RAM. If I set it to 8Mb, are you saying that Squid will use the rest of my 4Gb RAM as it sees fit? If so why have this setting? I'm missing the point here I'm sure, so please advise. Thanks, Ric
