Corrupted sizes in cache once again

[Marc]

Could even be memory. I had once on an office machine a faulty memory module (without ecc), and it caused the md5sum from files on truecrypt usb backup drives to change constantly. Removed the module, and no more issues.


> 
> Something to try, this all could be happening because of underlying disk
> failure on the array it is running on.  If this is a VM, can you move
> the operation to another host or data store to rule out hardware issues?
> 
> On 2/2/2023 9:19 AM, Stuart Henderson wrote:
> > On 2023-02-01, Tim Evers <te-ml-ext at artfiles.de> wrote:
> >> I run a fairly large Dovecot Installation (around 100k mailboxes) on
> >> several servers.
> >>
> >> gzip compression is on.
> >>
> >> Every once in a while I get the dreaded "cache corruption" messages in
> >> the log:
> >>
> >> Error: Corrupted record in index cache file
> >> /[redacted]/Maildir/dovecot.index.cache: UID 3868: Broken physical size
> >> in mailbox INBOX:
> >>
> read(zlib(/[redacted]/Maildir/cur/1674129792.M797543P21755.node2,S=8099,W=8276
> :2,))
> >> failed: Cached message size smaller than expected (2877 < 8099,
> >> box=INBOX, UID=3868)
> >>
> >> Error: Corrupted record in index cache file
> >> /[redacted]/Maildir/dovecot.index.cache: UID 3875: Broken physical size
> >> in mailbox INBOX:
> >>
> read(zlib(/[redacted]/Maildir/cur/1674212201.M985809P29112.node2,S=13907,W=141
> 21:2,))
> >> failed: Cached message size smaller than expected (5533 < 8192,
> >> box=INBOX, UID=3875)
> >>
> >> The first entry shows 2877 (size on disk) vs. 8099 (real size unzipped,
> >> also in the filename: S=8099).
> >>
> >> The second entry shows 5533 (size on disk) vs. 8192 - this is not
> >> correct in any way. Size on disk is 13907 as noted in the filename.
> >>
> >> Both mails were delivered trough LMTP and retrieved by the POP3 service.
> >>
> >> Anyone with an idea what might be happening here? I've read all
> >> available info in the doc and in the previous discussions / bug reports,
> >> but nothing seems to match my case. And where does that 8192 come from -
> >> it looks suspicious?
> >>
> >> Version is 2.3.7.2 (Ubuntu 20.04)
> > 2.3.7.2 is rather old now. There were definitely fixes regarding compression
> > around the 2.3.10-2.3.12 timeframe or thereabouts (I forget all the details
> > but it took a release or two before some remaining issues were sorted out
> > after changes in the area). I'd be looking to get it updated to a current
> > version first.
> >