Corrupt index files

[Robert Schetterer]

Am 21.07.2017 um 19:47 schrieb Bruce Guenter:
> 
> I am running Dovecot IMAP on Linux, on a LizardFS storage cluster with
> Maildir storage. This has worked well for most of the accounts for
> several months.
> 
> However in the last couple of weeks we are seeing increasing errors
> regarding corrupted index files.

you should avoid this
one solution is to use loadbalancers with persistance
and/or with i.e

https://wiki2.dovecot.org/Director

i dont know LizardFS
but problems are somekind equal with all storage clusters
and there are different solutions to handle
this so i dont know what may the best at your place

i would read and ask here for settings with storage clusters, a good
start could be

https://wiki2.dovecot.org/NFS
https://wiki2.dovecot.org/SharedMailboxes/ClusterSetup
https://wiki2.dovecot.org/MailLocation/SharedDisk



 Some of the accounts affected are
> unable to retrieve messages due to timeouts.

index settings and mailbox format has impact about this
maildir mostly is self healing but that may fail sometimes on cluster

> 
> It appeared the problems were due to the accounts being accessed from
> multiple servers simultaneously, so I forced them all to access one
> server, but the errors remained. It looks like it has something to do
> with file locking, but LizardFS supports advisory file locking and I do
> have it enabled.
> 
> Deleting the corrupted indexes fixes the problem for a while, but it
> eventually returns, particularly for some accounts.

yeah that is perhaps per design

> 
> Here are some errors I'm seeing (just a random grab). Actual home
> directories are munged for confidentiality.
> 
> imap[25157]: (clientes.standby) Error: Failed to fix view for HOME/clientes:standby/dovecot.index: Missing middle file seq=1 (between 1..1, we have seqs 8): File is already open
> imap[5565]: (stadiumchair) Error: Transaction log file HOME/stadiumchair/.Drafts/dovecot.index.log: marked corrupted
> imap[5005]: (stadiumchair) Error: Corrupted transaction log file HOME/stadiumchair/.Drafts/dovecot.index.log seq 2: indexid changed 1418941056 -> 1500658549 (sync_offset=0)
> imap[20243]: (martha) Error: Transaction log HOME/martha/dovecot.index.log: duplicate transaction log sequence (539)
> imap[4665]: (emsspam) Error: Index file HOME/emsspam/dovecot.index: indexid changed: 1500658479 -> 1297175382
> imap[4665]: (emsspam) Error: Corrupted transaction log file HOME/emsspam/dovecot.index.log seq 3: indexid changed: 1500658479 -> 1297175382 (sync_offset=316)
> imap[22985]: (emsspam) Error: Corrupted transaction log file HOME/emsspam/dovecot.index.log seq 10742: Invalid transaction log size (9296 vs 9296): HOME/emsspam/dovecot.index.log (sync_offset=9296)
> imap[3267]: (emsspam) Error: Failed to map view for HOME/emsspam/dovecot.index: Failed to map file seq=10742 offset=9052..18446744073709551615 (ret=0): corrupted, indexid=0
> imap[3267]: (emsspam) Error: HOME/emsspam/dovecot.index view is inconsistent: uid=3062271 inserted in the middle of mailbox
> 
> The output of dovecot -n is pasted in below. Note that some of the boxes
> are running 4.9, some running 4.4, all have the same problems. Also note
> that I am using a custom authentication front end for our virtual
> mailboxes, but it just sets up the minimal environment variables and
> runs imap.
> 
> Is there anything I can change to eliminate these problems? Are there
> any other diagnostics I can provide to shed light on this?
> 
> # 2.2.31 (65cde28): /etc/dovecot/dovecot.conf
> # OS: Linux 4.4.66 x86_64 Gentoo Base System release 2.3 
> log_path = /dev/stderr
> mail_debug = yes
> mail_fsync = always
> mail_location = maildir:~/.maildir
> mail_log_prefix = "%s[%p]: (%u) "
> mmap_disable = yes
> namespace inbox {
>   inbox = yes
>   location = 
>   mailbox Drafts {
>     special_use = \Drafts
>   }
>   mailbox Junk {
>     special_use = \Junk
>   }
>   mailbox Sent {
>     special_use = \Sent
>   }
>   mailbox "Sent Messages" {
>     special_use = \Sent
>   }
>   mailbox Trash {
>     special_use = \Trash
>   }
>   prefix = INBOX
>   separator = 
>   type = private
> }
> passdb {
>   args = *
>   driver = pam
> }
> passdb {
>   args = /etc/dovecot/dovecot-sql.conf.ext
>   driver = sql
> }
> plugin {
>   mail_log_events = delete undelete expunge copy mailbox_delete mailbox_rename
> }
> ssl_cert = </etc/ssl/dovecot/server.pem
> ssl_key =  # hidden, use -P to show it
> userdb {
>   driver = passwd
> }
> userdb {
>   args = /etc/dovecot/dovecot-sql.conf.ext
>   driver = sql
> }
> 

i think you could rare the corrupt
with optimize settings
to i.e

mail_fsync = always
mail_nfs_storage = yes
mail_nfs_index = yes
mmap_disable = yes

etc
but to fix it at all you may have to rethink your whole setup
dovecot gurus may help and search the list archive about cluster setups


Best Regards
MfG Robert Schetterer

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