Re: [squid-users] Duplicate If-None-Match headers

On 30/04/2012 14:32, Andy Taylor wrote:
> Hi,
>
> I'm having a number of problems with Squid at the moment with duplicate
> Etags in the headers. I'm using Squid as an accelerator to forward
> traffic to Apache, which serves up a Drupal installation.
>
> After roughly 3 days, a number of pages on the site start to fail with
> 400 Bad Request errors; it starts with just a few and then slowly
> spreads to more pages. I did a tcpdump of the requests coming from Squid
> to Apache, and Apache is spitting out a 400 error because of the header
> size. Hundreds of etags are appearing in the If-None-Match headers
> field, which hits Apache's header size limit, causing the error. The
> only way I've found to 'fix' this so far is to either:
>
> 1. Flush Squid cache entirely
> 2. Purge the affected pages
>
> But then after a few days the problem comes back again. I've been using
> Squid as an accelerator to Drupal installations for years and this
> hasn't happened before. I'm using the following version of Squid:
>
> Squid Cache: Version 2.6.STABLE21
>
> which is the latest version available in the CentOS 5 repositories. The
> only difference between this installation of Squid/Apache/Drupal and
> others which have worked fine in the past is the version of Drupal -
> Drupal 7. Supposedly Drupal 7 has significantly altered cache handling,
> but I can't work out why this would cause this problem with Squid.
>
> The only thing I can think of at the moment is something to do with
> Squid's cache rotation (specifically the LRU functionality), so that
> when Squid rotates its cache, something ends up corrupted or malformed.
>
> Any help or suggestions would be much appreciated!
>
> Thanks,
>
> Andy Taylor
i suppose that there are many changes since squid 2.6 and for me squid
3119 and 3216 works fine with drupal so i suppose you can try to compile
a more advanced and supported version of squid as a starter.

Eliezer

-- 
Eliezer Croitoru
https://www1.ngtech.co.il
IT consulting for Nonprofit organizations
eliezer <at> ngtech.co.il