Corrupted sizes in cache once again

[Christopher Wensink]

Can you isolate the problem account on a separate VM to see if the 
problem follows the account or the original vm?

Chris

On 2/2/2023 9:58 AM, Tim Evers wrote:
> Good point - these are 8 diferrent DRBD clusters. I failed over one 
> testing this theory. Problem persists.
>
> So I would rule out underlying issues.
>
> Especially since the "wrong" value is suspiciously often the on-disk 
> size rather than a random value one would expect if there is 
> corruption underneath.
>
> Tim
>
> Am 02.02.23 um 16:43 schrieb Christopher Wensink:
>> 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=14121:2,)) 
>>>>
>>>> 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.
>>>
>>>
>>>
>>

-- 
Christopher Wensink
IS Administrator
Five Star Plastics, Inc
1339 Continental Drive
Eau Claire, WI 54701
Office:  715-831-1682
Mobile:  715-563-3112
Fax:  715-831-6075
cwensink at five-star-plastics.com
www.five-star-plastics.com