On Wed, 22 Sep 2010 15:09:31 -0400, "Chad Naugle" <Chad.Naugle@xxxxxxxxxxx> wrote: > With that large array of RAM I would increase those maximum numbers, to > let's say, 8 MB, 16 MB, 32 MB, especially if you plan on using heap LFUDA, > which is optimized for storing larger objects, and trashes smaller objects > faster, where heap GSDF is the opposite, using LRU for memory for the large > objects to offset the difference. > > --------------------------------------------- > Chad E. Naugle > Tech Support II, x. 7981 > Travel Impressions, Ltd. > > > >>>> Rajkumar Seenivasan <rkcp613@xxxxxxxxx> 9/22/2010 3:01 PM >>> > Thanks for the tip. I will try with "heap GSDF" to see if it makes a > difference. > Any idea why the object is not considered as a hot-object and stored in > memory? see below. > > I have... > minimum_object_size 0 bytes > maximum_object_size 5120 KB > > maximum_object_size_in_memory 1024 KB > > Earlier we had cache_swap_low and high at 80 and 85% and the physical > memory usage went high leaving only 50MB free out of 15GB. > To fix this issue, the high and low were set to 50 and 55%. ? 50% empty cache required so as not to fill RAM? => cache is too big or RAM not enough. > > Does this change in "cache_replacement_policy" and the "cache_swap_low > / high" require a restart or just a -k reconfigure will do it? > > Current usage: Top > top - 14:33:39 up 12 days, 21:44, 3 users, load average: 0.03, 0.03, 0.00 > Tasks: 83 total, 1 running, 81 sleeping, 1 stopped, 0 zombie > Cpu(s): 0.0%us, 0.1%sy, 0.0%ni, 99.3%id, 0.0%wa, 0.0%hi, 0.0%si, > 0.6%st > Mem: 15736360k total, 14175056k used, 1561304k free, 283140k buffers > Swap: 25703960k total, 92k used, 25703868k free, 10692796k cached > > PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND > 17442 squid 15 0 1821m 1.8g 14m S 0.3 11.7 4:03.23 squid > > > #free > total used free shared buffers cached > Mem: 15736360 14175164 1561196 0 283160 10692864 > -/+ buffers/cache: 3199140 12537220 > Swap: 25703960 92 25703868 > > > Thanks. > > > On Wed, Sep 22, 2010 at 2:16 PM, Chad Naugle <Chad.Naugle@xxxxxxxxxxx> > wrote: >> Perhaps you can try switching to heap GSDF, instead of heap LFUDA. What >> are also your minimum_object_size versus your _maximum_object_size? >> >> Perhaps you can also try setting the cache_swap_low / high back to >> default (90 - 95) to see if that will make a difference. >> >> --------------------------------------------- >> Chad E. Naugle >> Tech Support II, x. 7981 >> Travel Impressions, Ltd. >> >> >> >>>>> Rajkumar Seenivasan <rkcp613@xxxxxxxxx> 9/22/2010 2:05 PM >>> >> I have the following for replacement policy... >> >> cache_replacement_policy heap LFUDA >> memory_replacement_policy lru >> >> thanks. >> >> On Wed, Sep 22, 2010 at 2:00 PM, Chad Naugle <Chad.Naugle@xxxxxxxxxxx> >> wrote: >>> What is your cache_replacement_policy directive set to? >>> >>> --------------------------------------------- >>> Chad E. Naugle >>> Tech Support II, x. 7981 >>> Travel Impressions, Ltd. >>> >>> >>> >>>>>> Rajkumar Seenivasan <rkcp613@xxxxxxxxx> 9/22/2010 1:55 PM >>> >>> I have a strange issue happening with my squid (v 3.1.8) >>> 2 squid servers with sibling - sibling setup in accel mode. What was the version in use before this happened? 3.1.8 okay for a while? or did it start discarding right at the point of upgrade from another? >>> >>> after running the squid for 2 to 3 days, the HIT rate has gone down. >>> from 50% HIT to 34% for TCP and from 34% HIT to 12% for UDP. >>> >>> store.log shows that even fresh requests are NOT getting stored onto >>> disk and getting RELEASED rightaway. >>> This issue is with both squids... >>> >>> store.log entry: >>> 1285176036.341 RELEASE -1 FFFFFFFF 7801460962DF9DCA15DE95562D3997CB >>> 200 1285158415 -1 1285230415 application/x-download -1/279307 >>> GET http://.... >>> requests have a max-age of 20Hrs. Server advertised the content-length as unknown then sent 279307 bytes. (-1/279307) Squid is forced to store it to disk immediately (could be a TB about to arrive for all Squid knows). >>> >>> squid.conf: >>> cache_dir aufs /squid/var/cache 20480 16 256 >>> cache_mem 1536 MB >>> memory_pools off >>> cache_swap_low 50 >>> cache_swap_high 55 These tell squid 50% of the cache allocated disk space MUST be empty at all times. Erase content if more is used. The defaults for these are less than 100% in order to leave some small buffer of space for use by line-speed stuff still arriving while squid purged old objects to fit them. The 90%/95% numbers were created back when large HDD were measured MB. 50%/55% with 20GB cache only makes sense if you have something greater than 250Mbps of new cachable HTTP data flowing through this one Squid instance. In which case I'd suggest a bigger cache. (My estimate of the bandwidth is calculated from: % of cache needed free / 5 minute interval lag in purging.) >>> refresh_pattern . 0 20% 1440 >>> >>> >>> filesystem is resizerfs with RAID-0. only 11GB used for the cache. Used or available? cache_dir...20480 = 20GB allocated for the cache. With 11GB is roughly 50% (cache_swap_low) of the 20GB. So that seems to be working. The 10MB/GB of RAM usage by the in-memory index is calculated from an average object size around 4KB. You can check your available RAM roughly meets Squid needs with: 10MB/GB of disk cache + the size of cache_mem + 10MB/GB of cache_mem + about 256 KB per number of concurrent clients at peak traffic. This will give you a rough ceiling. Amos
