Hi, On Thu, 27 Aug 2009, Chris Robertson wrote: > It will if you can fill them without overloading the cache index. Each > object in the cache needs to be indexed in memory. The 10MB of RAM per > GB of disk space assumes an average object size of 10KB. Using that > rule of thumb, you'd need 100GB of RAM for a 10TB cache (just for the > index)! This rule of thumb may be reasonable, but the average object size seems too low to me. We see an 80KB average object size, which suggests something more like 1.25MB per GB. We have 1GB as our disk cache max object size which doubtless does expand the average. If you want high byte hit rate you need to cache large objects. We have an 800GB cache (2x400GB on two 1TB disks) and although there's 8GB of ram, it's on a 32-bit operating system (so squid's process size can't go above 3GB). The above value suggests the indexes take up about 1GB of RAM. We have a 1GB memory cache and all runs fine without swapping so the index must be fitting into 2GB. Gavin
