On Wed, 22 Sep 2010 15:09:31 -0400, "Chad Naugle"
<Chad.Naugle_at_travimp.com>
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_at_gmail.com> 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_at_travimp.com>
> 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_at_gmail.com> 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_at_travimp.com>
>> wrote:
>>> What is your cache_replacement_policy directive set to?
>>>
>>> ---------------------------------------------
>>> Chad E. Naugle
>>> Tech Support II, x. 7981
>>> Travel Impressions, Ltd.
>>>
>>>
>>>
>>>>>> Rajkumar Seenivasan <rkcp613_at_gmail.com> 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
Received on Thu Sep 23 2010 - 04:21:48 MDT
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