Re: [squid-users] ipcCreate: fork: (12) Cannot allocate memory

On Sat, 19 Mar 2011, Amos Jeffries wrote:

> On 19/03/11 02:43, Winfield Henry wrote:
>>
>> Hi,
>> Squid has started to NOT come back up after log rotate. Here is snippett
>> from cache.log.
>> Machine has 1G ram and cache_mem is set to 500MB,
>
> Squid uses fork() instead of vfork() to spawn helpers, on some OS the fork()
> implementation prevents extremely huge amounts of virtual memory being
> "allocated" (even though it is neither allocated nor used).

I think you mean that on some OS the form implementation 'results in'
rather than 'prevents'

on linux this is the 'overcommit' option, on by default in the kernel, but
many people think it makes their systems more reliable to disable it.

you can work around the problem by makeing sure the system has enough
virtual memory available, usually by increasing the amount of swap space
avialable.

David Lang

> The helper multiplexer has been created to get around this problem:
> ftp://ftp.squid-cache.org/pub/squid/contrib/helper-mux/
> Details on how to use it are in the Squid-3.2 release notes:
> http://www.squid-cache.org/Versions/v3/3.2/RELEASENOTES.html
> (published as part of 3.2, but works on all squid-2.6 or later).
>
> PS.
> A few of use have looked at making Squid use vfork() but been defeated by
> the parent doing followup logics. If anyone is keen to attack the problem
> patches that work will be VERY welcome.
>
> Amos
>
Received on Fri Mar 18 2011 - 23:23:55 MDT