Re: [squid-users] squid3 SMP aufs storage/process

On 03/09/2013 09:19 AM, Adam W. Dace wrote:

> being able to use configuration like this sure makes it easier:
>
> # Uncomment and adjust the following to add a disk cache directory.
> cache_dir aufs /usr/local/squid/var/cache${process_number}/squid 1024 16 256

One should also add squid.conf conditional to exclude the above line
from being seen by the Coordinator process. Here is a sketch:

    if ${process_number} = <coordinator process number here>
        # do nothing -- this is Coordinator
    else
        # configure all SMP-unaware, non-shared cache_dirs here
        cache_dir aufs ...${process_number}...
    endif

Otherwise, Coordinator will create (during squid -z) and then open the
corresponding cache_dir, creating confusion and possibly running into bugs.

HTH,

Alex.

> On Sat, Mar 9, 2013 at 1:48 AM, jiluspo <jiluspo_at_smartbro.net> wrote:
>> Therefore squid SMP is not stable. if we need to store more than 32KB the
>> best way is to use multi-instance and peering...I wish I could use multicast
>> in localhost.
>>
>> When would probably finish the rock for large content?
>>
>> I've tried in production squid3head SMP rock storage only and crashed with
>> BUG 3279: HTTP reply without Date:
>>
>> @1kreq/sec squid3(storied worker2) vs squid2(storeurl) coss..... squid2 gets
>> higher hit.
>> And to be honest. Squid2head runs more stable than squid3 stable.
>>
>>> -----Original Message-----
>>> From: Alex Rousskov [mailto:rousskov_at_measurement-factory.com]
>>> Sent: Saturday, March 09, 2013 3:03 PM
>>> To: squid-users_at_squid-cache.org
>>> Subject: Re: [squid-users] squid3 SMP aufs storage/process
>>>
>>> On 03/08/2013 11:21 PM, jiluspo wrote:
>>>
>>>> If squid3 configured with cache_dir aufs per process would they
>>>> share to other process?
>>>
>>> No. Ufs-based store modules, including aufs, are currently not
>>> SMP-aware. If you use them in SMP Squid (without protecting them with
>>> SMP conditionals), your cache will get corrupted.
>>>
>>> SMP conditionals in squid.conf can be used to prevent corruption, but
>>> they also prevent sharing of cache_dirs among workers.
>>>
>>> Rock store and memory cache are SMP-aware, share cache among workers,
>>> and do not need SMP macros, but they have their own limitations (we are
>>> actively working on addressing most of them).
>>>
>>>
>>> Pick your poison,
>>>
>>> Alex.
>>>
>>> Email secured by Check Point
>>
>
>
>
Received on Mon Mar 11 2013 - 20:12:00 MDT