On 1/27/20 1:52 PM, netadmin wrote: > reply_body_max_size 20 MB localnet I would not set this option unless there is a good reason for setting it. > maximum_object_size_in_memory 20 MB If you want to cache objects that approach 20MB in body size, then raise this to at least 21MB to account for overheads. The overheads (e.g., HTTP headers) are not that large, but it is easier and safer than computing them directly. > read_ahead_gap 20 MB FYI: Due to Squid implementation deficiencies/limitations, a huge gap like this is likely to cause large, unpooled memory allocations on virtually every received HTTP response with a body, regardless of that response body size. This should not cause bugs or transaction aborts, but you should be aware of the high performance cost of such allocations, including stalling the entire Squid worker for a few milliseconds (at least). > If I try to download a 20 MB file on all workstations at the same time, > without the option "read_ahead_gap 20 MB", the download fails on a small > number of workstations. This is an indication of a bug somewhere. The usual suspects are: Squid, the ICAP service, the HTTP origin server. > If I use disk storage for the 20 MB file, during the simultaneous download > the processor load reaches 100% - this I think not because of the ICAP > server - and download errors occur. Persistent 100% CPU usage with 20 concurrent transactions on decent hardware is also a red flag. > Is the maximum supported size for a file transmitted to the ICAP server 20 > MB? No. There is virtually no maximum. > Is there anything wrong with my settings? What you want should "work" (in principle) without any special settings. And it should work with/through a memory cache given a large-enough maximum_object_size_in_memory setting. Some of your settings might stress Squid because they set very tight limits for 20MB objects, with no room for overheads (see above for specifics), but even that should not really break things (especially in your non-SMP setup) -- it may cause more cache misses and such. I would suspect a bug (possible, but not necessarily in Squid). Analyzing a cache.log with debug_options set to ALL,9 will probably be enough to pin-point the culprit but may require some developer knowledge/effort because those 20 concurrent transactions will create a lot of debugging noise. Alex. _______________________________________________ squid-users mailing list squid-users@xxxxxxxxxxxxxxxxxxxxx http://lists.squid-cache.org/listinfo/squid-users
