Hi, I searched for some time the archives, but still I have some questions concerning the choice of cache_mem and L1, L2. maybe someone can help me understand:
a) is this formula still correct: L1 = cache_size *2*1024 / (L2*L2*average_object_size) with a saftey margin of factor 2? in the L2 directories: will there always be a number of L2 files (as a maximum)? b) is it correct that L2 should be 254 instead of 256 on linux/ext2 systems? what about reiser fs? c) is ist correct that for one object squid holds 72 Bytes (intel,sparc) data in memory for metadata? somewhere i read, squid uses only the hashlist of the md5 checksums in order to find the objects, somewhere else i read, squid uses the metadata + md5 checksum in memory. what is right? given 72 bytes - there is about 10 MB metadata memory used for 1 GB file cache. right? d) in squid.conf, there is the default entry cache_dir ... 100 16 256 but by the formula in a), given these values (100 mb and L2=256, 13 kb av_ob_si), L1 should be about only 1. why then these values are chosen as defaults? e) what about the value of cache_mem (default: 8mb)? since it is only used for hot, intransit, and negative-cached objects, what is the best value? given cache_size = 1gb and ram size = 1gb, what should be the value of cache_mem? somewhere i read, that if cache_mem is too high, there might be swapping with negative effects for squid - why would this be so? if i reserve 512 mb of 1gb ram for squid - then 10 mb would be for metadata, maybe another 20 mb for other squid needs. should i then use (512-10-20) mb for cache_mem in order to increase performance? f) at last: the low and high watermarks - are they only used for file cache or also for the memory used for cache_mem? can i chooce any of the 4 cache replacement policies for file cache also for cache_mem? you see, there are a lot of things i still do not fully understand. thx in advance,
