Re: Squid Startup Requirement

Saleem Ahmed Khan wrote:
> Hi Amos,
>
> We have been working on squid-2.6.STABLE18 and as this been already
> deployed, changes are required to done on this.

Fair enough. Just checking before things went far down the development
track.

>
> To fulfill this requirement currently i am putting a check in
> "parse_cachedir" function of cache_cf.c to see if the cache directories
> specified in squid.conf are present or writable by using stat system
> call. Based on the true condition I am allocating the swap directories
> or returning from the function.

Sounds correct to me.

> With this modification I am able to start the squid even with the
> unwritable cache directories and caching seems to be happening when i
> tested, I would further confirm about this.
> As per the requirement I feel this is being addressed, sure if you can
> further put some light on this.

Okay. Limiting to startup problems, you are right, has a small scope and
easily addressed.

I was thinking of the feature requests we already had from others about
running-time cache_dirs loss. The startup issue you are fixing was not
mentioned then. http://wiki.squid-cache.org/Features/CacheDirFailover

If you want to present the patch to squid-dev. Even one for 2.6. I'll
see whats needed to port it to 3.x. I expect Henrik may accept it into
2.7 since its a stability issue.

Skipping back to the errors you mentioned earlier. Are they resolved or
still confusing you?

Thank you for the work.

Amos

>
> Regards
> Saleem
>
> On Thu, Apr 17, 2008 at 6:33 PM, Amos Jeffries <squid3@treenet.co.nz
> <mailto:squid3@treenet.co.nz>> wrote:
>
> saleem_ak wrote:
>
> I am currently working on requirement if any of the cache
> directories are
> unavailable or unwritable, squid will not start. We would like
> the squid to
> only refuse to start if "no" cache_dirs are available - if more
> than one is
> configured but some are unavailable, we'd like it to log the
> error and
> continue on with the known-good cache_dir(s).
>
> I am able to do the required changes by having a global counter
> to track the
> clean cache directories and based on the counter value not equal
> to zero i
> am allowing squid to start.
>
>
> You may encounter problems in future with this feature as described.
> All releases of squid have an integrated memory-cache. Recent
> releases of squid work on the basis that if no cache_dir are present
> the memory cache is configured.
>
> You will need to add an option to your feature to cope with that
> state. For example; when turned on squid ignores cache_dir loss and
> drops right back into memory-cache, but keeps running. When setting
> turned off, drops back but ignores memory-cache and dies.
>
> But I am facing these problems
> 1) the directory cleanup event is trying to cleanup the
> unavailable or
> unwritable cache directories
> 2) the objects are tried to cached into the unavailable or
> unwritable cache
> directories.
>
> As I am new to the squid, I would like to get some proper
> direction to
> fulfill this requirement.
>
>
> Is the version of squid important?
> This is a major feature, and faces a large hurdle now with squid-2
> being closed to large patches.
> Adrians was the last developer working on major new features for
> Squid-2 and even he has recently decided to abandon direct major
> updates to Squid-2 in favor of a different project.
>
> Squid-3 has a very different storage code, and is likely to be the
> place where your patch is accepted into squid. The Squid-3 design
> can also handle failover cases cleaner.
>
> I am also mentioning the error messages that i am getting with
> this change
>
> error messages got after the startup 008/04/15 10:41:31|
> storeDirClean: WARNING: Creating
> /usr/local/squid.2.6_cachedir/cache/05/69 2008/04/15 10:41:31|
> storeDirClean: /usr/local/squid.2.6_cachedir/cache/05/69: (2) No
> such file
> or directory
>
> this messages are coming during object caching 2008/04/17
> 06:35:39| storeAufsOpenDone: (2) No such file or directory
> 2008/04/17 06:35:39|
> /usr/local/squid.2.6_cachedir/cache/00/00/0000005E
> 2008/04/17 06:35:39| storeSwapOutFileClosed: dirno 5, swapfile
> 0000005E,
> errflag=-1
>
> Regards
> Saleem
>
>
> Amos
> --
> Please use Squid 2.6.STABLE19 or 3.0.STABLE4
>
>
>
>
> --
> Thanks and Regards
> Saleem Ahmed Khan
> +919972522504

-- 
Please use Squid 2.6.STABLE19 or 3.0.STABLE4