Re: corrupt cache

From: pstewart <pstewart@dont-contact.us>
Date: Thu, 12 Jun 1997 14:42:10 -0400 (EDT)

I seen this once or twice here but then it just went away..:-) It was
shortly after we doubled up the cache...

I have another problem that might be related to what you are describing...
on certain sites (Microsoft is worse than others I *think* due to constant
cookies being transmitted) it will give a read error on the site almost
immediately. Then when you try again it immediately is fine.

Is there a timeout and/or retry setting in the squid.conf file that I can
adjust to tell it to try a couple of times before giving up?

Thanks again,

Paul

--
Out the modem, through the SPARC, down the T3, off the router, past the
frame-relay... nothing but Net.
On Thu, 12 Jun 1997, Andreas Strotmann wrote:
> On Jun 12, 16:08, Peter van Empel wrote:
> > Subject: corrupt cache
> >
> > Then we looked in our cache.log and saw a lot of warnings:
> > 97/06/05 10:42:23| storeSwapInHandle: WARNING: Object size mismatch.
> > 97/06/05 10:42:23|   --> 'http://cwis.kub.nl/~dbi/cwis/inf/index.htm'
> > 97/06/05 10:42:23|   --> Expecting 5330 bytes from file:
> /cache/0A/53/0000053A
> > 97/06/05 10:42:23|   --> Only read 2328 bytes
> > 97/06/05 10:42:23| storeSwapInHandle: WARNING: Object size mismatch.
> > 97/06/05 10:42:23|   --> 'http://cwis.kub.nl/~dbi/cwis/gifs/help.gif'
> > 97/06/05 10:42:23|   --> Expecting 1276 bytes from file:
> /cache/0D/53/0000053D
> > 97/06/05 10:42:23|   --> Only read 1944 bytes
> > 97/06/05 10:42:23| storeSwapInHandle: WARNING: Object size mismatch.
> > 97/06/05 10:42:23|   --> 'http://cwis.kub.nl/~drc/gifs/knoplhom.gif'
> > 97/06/05 10:42:23|   --> Expecting 1558 bytes from file:
> /cache/07/19/00000197
> > 97/06/05 10:42:23|   --> Only read 6044 bytes
> >
> >
> > This seems the problem. Squid is detecting that a certain objectsize is
> not
> > correct but still it served the files out. When it detects some
> > inconsistencies it has to refresh it, or deny this request , but never
> serve
> > them out!
> > A warning in a log is not enough, because at last a complete cache is
> getting
> > corrupt.
> >
> > In the past we had seen FATALS like:
> > FATAL: Received Segment Violation...dying
> > FATAL: Received Bus Error...dying
> >
> 
> The last time I saw something like that (in a very early version of
> Squid), this had happened:
> 
> A buffer overflow had overwritten the name field for the cache/log file,
> causing the update for that file to be written to cache/<something_else>
> instead of cache/log.  After stopping and restarting Squid, an _old_
> version of the cache/log file is then used -- namely, the one that had not
> been overwritten.
> 
> So-- check for files with strange names in the place where your cache/log
> file should reside, and perhaps move the most recent such file to
> cache/log.  (However, this is a solution only if you immediately recognize
> the problem when it happens.  Otherwise, you will probably need to delete
> the cache/log and restart Squid.
> 
> I had the impression (when this happened last to me) that Squid indeed
> refuses to serve items with size mismatches.  Unfortunately, it sometimes
> happens that an object is overwritten with one that has the same size.
>  Given the typical size distribution and a huge cache (mine currently has
> more than 500000 objects in it), this is quite likely to happen in a few
> cases.
> 
> Hope this helps,
> 
> Andreas
> 
> -- 
> Andreas Strotmann       / ~~~~~~ \________________A.Strotmann@Uni-Koeln.DE
> Universitaet zu Koeln  /| University of Cologne   \
> Regionales Rechenzentrum| Regional Computer Center \
> Robert-Koch-Str. 10    /|    Tel: +49-221-478-5524 |\   Home: -221-4200663
> D-50931  Koeln        __|__  FAX: +49-221-478-5590 |__________~~~~~~~~~~~~   
> 
Received on Thu Jun 12 1997 - 11:46:18 MDT

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