Fw: SMP cache memory

>Shared memory cache in official Squid releases does not support storing
>objects larger than 32KB. This limitation is unrelated to cache_dirs in
>use.
Understood, so objects larger than 32k can not use shared memory cache.
There is something to do to be able to use shared memory cache with large
objects?

>> mgr:storedir
>> Shared Memory Cache
>> Maximum Size: 26214400 KB
>> Maximum entries: 819200
>> Current entries: 477472 58.29%

>You quoted one mgr:storedir response. It indicates that the shared
>memory cache is 58% full and can accept more entries. What do TWO cache
>manager mgr:storedir queries, sent a few hours apart, show?

Shared Memory Cache
Maximum Size: 26214400 KB
Maximum entries: 819200
Current entries: 502242 61.31%

Thanks very much,
Dzieva.

-----Mensagem Original-----
From: Alex Rousskov
Sent: Thursday, September 26, 2013 12:13 PM
To: squid-dev_at_squid-cache.org
Subject: Re: SMP cache memory

On 09/25/2013 06:49 PM, Marcos A. Dzieva wrote:
>> FYI: The shared memory cache cannot store objects exceeding 32KB in
>> size. The pending Large Rock changes will remove that limitation.
> When LargeRockStore be ready?

The following wiki page reflects the current status:
http://wiki.squid-cache.org/Features/LargeRockStore

> It seems that when using workers and cache_dir aufs ... objects larger
> than 32K had not been in cache memory, remained only on hard disk.
> And the objects larger than 32K being written by cache_dir aufs ... not
> share the memory cache?

Shared memory cache in official Squid releases does not support storing
objects larger than 32KB. This limitation is unrelated to cache_dirs in use.

>> What do two cache manager mgr:storedir queries, sent a few hours apart,
>> show? Does the memory cache grow? Does Squid think the shared memory
>> cache is full?
>
> mgr:storedir
> Shared Memory Cache
> Maximum Size: 26214400 KB
> Maximum entries: 819200
> Current entries: 477472 58.29%

You quoted one mgr:storedir response. It indicates that the shared
memory cache is 58% full and can accept more entries. What do TWO cache
manager mgr:storedir queries, sent a few hours apart, show?

Thank you,

Alex.

> -----Mensagem Original----- From: Alex Rousskov
> Sent: Wednesday, September 25, 2013 4:42 PM
> To: squid-dev_at_squid-cache.org
> Cc: Marcos A. Dzieva
> Subject: Re: SMP cache memory
>
> On 09/25/2013 08:56 AM, Marcos A. Dzieva wrote:
>
>> Because my machine squid does not use the entire memory (cache_mem 25600
>> MB), + - 3GB is used?
>
> This sounds like a squid-users@ question rather than a squid-dev@ one,
> but is it possible that your traffic just does not have enough objects
> between 1KB and 32KB in size to fill 25GB of RAM cache? One way to test
> that theory is to study access logs. Another is to start Squid without
> workers but lower the maximum_object_size_in_memory limit to 32KB to
> mimic the shared memory cache limitation.
>
>
>> memory_replacement_policy heap GDSF
>
> FYI: The above has no effect on shared memory cache.
>
>
>> maximum_object_size_in_memory 10240 KB
>
> FYI: The shared memory cache cannot store objects exceeding 32KB in
> size. The pending Large Rock changes will remove that limitation.
>
>
> What do two cache manager mgr:storedir queries, sent a few hours apart,
> show? Does the memory cache grow? Does Squid think the shared memory
> cache is full?
>
>
> HTH,
>
> Alex.
Received on Fri Sep 27 2013 - 01:00:27 MDT