Corrupted sizes in cache once again

Christopher Wensink cwensink at
Thu Feb 2 15:43:37 UTC 2023

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> 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 (Ubuntu 20.04)
> 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

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