February 2023 - dovecot

Roundcube <-> Dovecot timeouts under very moderate load on big Dovecot nodes
by Malte Schmidt 18 Feb '23

18 Feb '23

Due to a recent topic regarding the performance of the Roundcube webmailer with Dovecot as a backend, I set up imapproxy successfully, shrinking the response latency of the webmailer heavily, which is great. However, I still encounter strange timeouts on some requests when Roundcube tries to access Dovecot. Be it for authentication or to FETCH data. I run the tests/benchmarks via distributed JMeter from 4 nodes, they access the webmailer which in turn accesses the Dovecot via imapproxy. There are 16 different mailaccounts spread over two dovecot nodes with the first one acting as a proxy if the account resides on the second. The problems start at around 100 concurrent users and gets worse the more users are added. The timeouts make up for a small percentage of the requests (0.0something percent). The timeout is reached after 30 seconds of Dovecot not answering, due to the timeout set in the webserver the webmailer is running on. Now I am wondering how to further debug this and what could be the reason. Some requests towards Dovecot are certainly taking longer than 30 seconds, while the average request takes mostly less than 1. The Dovecot is running on two big hardware machines with 48 cores, 96G memory and SSD storage. The load on the Dovecot nodes while the test is running is minimal. Best regards, M. Schmidt

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dovecot_login accepts blank password for exim smtp auth
by Jeff Rogers 18 Feb '23

18 Feb '23

Hi all, I recently discovered a configuration issue on my system where a system user account had a blank rather than invalid or disabled password in the passwd/shadow database. The user could not be logged into through login/telnet/ssh because it was marked as a system account (uid < 100). Dovecot also would not authenticate the user for the same reason. However, I'm using exim using dovecot_login for authentication, and that would authenticate the user with a blank and allow me to be used as an open relay. This is clearly a config issue on my part (since fixed), but should dovecot_login guard against blank passwords or system users just as a normal login does? I'm running dovecot 2.2.36 (1f10bfa63) Exim version 4.96 I don't know which software supplies the dovecot_login connenector. The SMTP session would include AUTH LOGIN 334 VXNlcm5hbWU6 cG9zdGZpeA== 334 UGFzc3dvcmQ6 <-- nothing, just a return here 235 Authentication succeeded DONE

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Special authentication use case
by Philippe MARASSE 17 Feb '23

17 Feb '23

Folks, I'm trying to configure dovecot SASL with two use cases : - First with XOAUTH2 : I've managed to get it working, pretty right out of the box, developers have done a great job :-) - Second with Client TLS Certificate with no luck. Let me explain, the certificate brought by the client does not have any clue of associated email, I have to check that username (=email) sent by the client is really related to some information included in the certificate (I have to extract the OU and then lookup into a table of authorized mails for that OU). Is it possible to do that with dovecot ? I think yes but I'm looking for direction to achieve that. Lua maybe ? Our configuration : - OS : Debian 11 $ /usr/sbin/dovecot --version 2.3.13 (89f716dc2) Regards. -- Philippe MARASSE Responsable pôle Infrastructures - DSIO Centre Hospitalier Henri Laborit CS 10587 - 370 avenue Jacques Cœur 86021 Poitiers Cedex Tel : 05.49.44.57.19

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Re: SOLVED: Re: Dovecot does not start on MacOS 12.01, and now 13.2.1 - RLIMIT_DATA
by James Brown 17 Feb '23

17 Feb '23

Sorry, replying to an old thread found on mail-archive.com <http://mail-archive.com/>, so it’s not threaded email. https://www.mail-archive.com/dovecot@dovecot.org/msg84776.html I have just installed Dovecot onto Mac Studio running Ventura (macOS 13.2.1) and get the same error with Dovecot 2.3.20: service(log): Fatal: setrlimit(RLIMIT_DATA, 268435456): Invalid argument Adding the ’service log’ stanza to 10-master.conf fixed the issue. Is this still the correct way to handle it? If so it would be great to have it documented somewhere. Just lucky I found the above mail thread. Thanks, James. Hi! That solution is bit overly broad way to solve this, I would instead recommend service log { vsz_limit = 0 } so that only service log is affected. Aki > On 31/10/2021 20:36 Don Feliciano <don.felici...(a)icloud.com> wrote: > > > > A kind person who isn’t on the mailing list share the solution to this with > me: > > default_vsz_limit = 0 > > > > On Oct 28, 2021, at 12:12 PM, Don Feliciano <don.felici...(a)icloud.com> > > wrote: > > > > > > Warning: fd limit (ulimit -n) is lower than required under max. load (256 < > > 1000), because of default_client_limit > > Oct 28 12:08:48 service(log): Fatal: setrlimit(RLIMIT_DATA, 268435456): > > Invalid argument > > > > > > > On Oct 27, 2021, at 11:08 AM, Don Feliciano <don.felici...(a)icloud.com> > > > wrote: > > > > > > I've been happily running Dovecot on my Mac for many years (installed via > > > Homebrew). After upgrading to Monterey (MacOS 12.01), it no longer starts: > > > > > > $ sw_vers > > > ProductName: macOS > > > ProductVersion: 12.0.1 > > > BuildVersion: 21A559 > > > > > > $ uname -a > > > Darwin dfelicia-mac 21.1.0 Darwin Kernel Version 21.1.0: Wed Oct 13 > > > 17:33:23 PDT 2021; root:xnu-8019.41.5~1/RELEASE_X86_64 x86_64 > > > > > > $ sudo dovecot -F > > > Oct 27 10:11:18 service(log): Fatal: setrlimit(RLIMIT_DATA, 268435456): > > > Invalid argument

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Could not override "mail_location" with "userdb_mail" statment in "/etc/passwd"
by Xavier 17 Feb '23

17 Feb '23

Hi, ** Using Dovecot 2.2.22 and Postfix 3.1.0 ** I plan to migrate all accounts on my server from mbox to maildir storage but before i want to make some tests on dedicated accounts. To do so i want to overide the general "mail_location" ( mail_location = mbox:~/mail:INBOX=/var/mail/%u ) with "maildir:~/Maildir" only for some test accounts. To do so i modified my "/etc/passwd" file using something like that : testm2m_mydomain.tld:x:2122:2122::/home/mail/testm2m_mydomain.tld:/bin/false:userdb_mail=maildir:~/Maildir Also tried testm2m_mydomain.tld:x:2122:2122::/home/mail/testm2m_mydomain.tld:/bin/false::userdb_mail=maildir:~/Maildir And as mentioned in the doc (https://wiki.dovecot.org/LDA/Postfix) i added -d "$USER" in my Postfix "mailbox_command" but it don't seem to work (my new mail_location for this test user is is not taken into account). When i try to make an "doveadm user testm2m_mydomain.tld" i get this : 8<-------------------------------- field value uid 2122 gid 2122 home /home/mail/testm2m_mydomain.tld mail mbox:~/mail:INBOX=/var/mail/testm2m_mydomain.tld system_groups_user testm2m_mydomain.tld 8<-------------------------------- My modification is not taken into account ... Any help is welcome ! /Xavier

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dovecot director how to obtain hashed
by tomate aceite 16 Feb '23

16 Feb '23

Morning again! Working with my directors node. Does anybody now how to obtain a list of all users hashes? I know how to obtain for one user example: *doveadm director status user@domain* I am looking to a way or command to take a list of hashed epired (1)#: doveadm director status manolito@mydomain > Current: 10.X.X.108 (expires 2023-02-17 12:17:59) > Hashed: 10.X.X.108 > Initial config: 10.X.X.108 > Where are stored the hashed ? To lock for the info , etc... Thanks in advance!!!

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Error: Broken file dovecot-uidlist
by Sohin Vyacheslav 16 Feb '23

16 Feb '23

Hi All, In mail.log are exists error messages "Error: Broken file /data/mail/vhosts/domain.com/user(a)domain.com/Maildir/dovecot-uidlist line XX: Invalid data: for some email accounts. For example, dovecot-uidlist line 21197: Invalid data: When I open line 21197 in editor: # vim +21197 dovecot-uidlist 1750207 :1676454069.M698819P4439.mail-b,S=963716,W=976359 and then check this file size # ls -l /data/mail/vhosts/domain.com/user@domain.com/Maildir/cur/1676454069.M698819P4439.mail-b,S=963716,W=976359:2,S -rw------- 1 vmail vmail 963716 Feb 15 10:41 I see that size is the same: 963176 bytes. So what exactly mentioned in error message "dovecot-uidlist line 21197: Invalid data:"? -- Best wishes Sohin Vyacheslav

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Corrupted sizes in cache once again
by Tim Evers 15 Feb '23

15 Feb '23

Hi, 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) doveconf -n excerpt: protocol lmtp { mail_plugins = " old_stats mail_log notify zlib sieve quota" } protocol imap { mail_max_userip_connections = 50 mail_plugins = " old_stats mail_log notify zlib imap_old_stats quota imap_quota imap_sieve" } protocol pop3 { mail_max_userip_connections = 50 mail_plugins = " old_stats mail_log notify zlib" } Tim

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Error: Corrupted index cache file
by Sohin Vyacheslav 15 Feb '23

15 Feb '23

Hi All, In mail.log exists an error messages "Error: Corrupted index cache file /data/mail/vhosts/domain.com/user(a)domain.com/Maildir/dovecot.index.cache: invalid record size" for some accounts. I tried these steps to fix it: 1. Running commands # doveadm -D -v index -u user(a)domain.com INBOX # doveadm -v force-resync -u user(a)domain.com INBOX after this I saw that the following files are updated in ../Maildir/: dovecot.index.cache dovecot.index.log dovecot-uidlist But after some time error messages occurred again. 2. Added NFS mount option 'nordirplus' to /etc/fstab with remount /data partition, add 'mmap_disable = yes' and 'mail_fsync = always' to 10-mail.conf as advised on https://doc.dovecot.org/configuration_manual/nfs/ (because /data partition mounted via NFS); 3. Renaming 3 files with/without Dovecot service pre-stop. # mv dovecot.index old.dovecot.index # mv dovecot.index.cache old.dovecot.index.cache # mv dovecot.index.log old.dovecot.index.log Unfortunately, all done steps didn't fix issue. What is the proper way to fix corrupted index cache errors? dovecot package: 1:2.2.33.2-1ubuntu4.8 (Ubuntu-18.04). p.s. for some of email accounts also exists error messages "Error: Broken file ../Maildir/dovecot-uidlist line ###: Invalid data:" besides mentioned cache error. -- Best wishes Sohin Vyacheslav

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NFS and performances
by tomate aceite 15 Feb '23

15 Feb '23

Hello, i have some question about NFS, dovecot director, and imap settings. I was reading all dovecot documentation ad mail lists, but some aspect are not clear to me. I am looking for performance / tunning my infra to work in a more efficient way because we experiences some issues some days ago. This is my infra: I got an infra with 2 dovecot-directors and 3 imap backend. I got all the emails stored in a common NFS share filer to all the imap nodes. ( Index are locally stored in each imap node.) My NFS mount options: (0)#: nfsstat -m /data/mail from myipaddress:/export/mail/maildirs > Flags: > rw,nosuid,noexec,noatime,vers=3,rsize=1048576,wsize=1048576,namlen=255,hard,nordirplus,proto=tcp,timeo=600,retrans=2,sec=sys,mountaddr=10.0.0.205,mountvers=3,mountport=20048,mountproto=tcp,local_lock=none,addr=10.0.0.205 > *Questions*: ( https://wiki.dovecot.org/PerformanceTuning , https://doc.dovecot.org/configuration_manual/nfs/ >> i am following these steps ) 1) Is my NFS correct setup with the mount options well optimized ? Not sure if someone is using the same flags that me or got a better recomendation to used. 2) Set *mmap_disable = yes ??? * >> This must be set to yes if you store indexes to shared filesystems. In my case i got them locally in each imap node not in NFS share folder. I got setup mmap_disable = no , is this correct? I think no is the correct option here with indexes locally. because i can read here: https://wiki1.dovecot.org/NFS > > >> High performance NFS setup with indexes on local disk (see below for > benefits): > > mmap_disable = no > 3) Set* mail_fsync = always ???* Documentation: https://wiki.dovecot.org/PerformanceTuning always > > Use fsync after all disk writes. > > Recommended for NFS to make sure there aren’t any delayed write()s. > 3.a) where i can setup this option *mail_fsync = always , *because i run doveconf -n in director, and imap nodes, and they are not showing nothing. 3.b) *In which node ? *Do i need to add the setting in dovecot.conf in *director node or in imap node or in both ?* Not sure if this is the correct way: This is an attemp of setup, not sure if is correct? 0)#: doveconf -n > # 2.3.13 (89f716dc2): /etc/dovecot/dovecot.conf > # Pigeonhole version 0.5.13 (cdd19fe3) > # OS: Linux 5.10.0-20-amd64 x86_64 Debian 11.6 > > mail_debug = yes > mail_fsync = always > mail_max_userip_connections = 20 > mail_nfs_storage = yes > mail_plugins = " notify mail_log" > mail_privileged_group = mail > > > > protocol lmtp { > mail_fsync = always > mail_plugins = " notify mail_log sieve mail_lua push_notification > push_notification_lua" > plugin { > ... > } > 4) Do not set *mail_nfs_index *or *mail_nfs_storage* (i.e. keep them as no) ????? First option make sense but the second one not. https://doc.dovecot.org/settings/core/#core_setting-mail_nfs_storage mail_nfs_storage >>> >>> Default: no >>> >>> Values: Boolean >>> >>> Flush NFS caches whenever it is necessary to do so. >>> >> > This setting should only be enabled if you are using multiple servers > on NFS. > So should be possible to enable this option *mail_nfs_storage = yes ?????* 4) I got this setting in *dovecot-sql.conf ( director ) * driver = mysql > connect = host=myserver.X dbname=maildb user=dovecot > password=XXXXXXXXXXXXXXXX > default_pass_scheme = SHA > password_query = select login as user, crypt_sha1 as password, home as > userdb_home, uid AS userdb_uid, gid AS userdb_gid, > concat(maildir,':INDEX=/data/indexes/',login) as userdb_mail from mailbox > left join aliases on aliases.systemid = aliasid where login = '%u' and > inactive = 0; > user_query = select home, maildir as mail, uid, gid from mailbox left join > aliases on aliases.systemid = aliasid where login = '%u' and inactive = 0; > iterate_query = select distinct login as user from mailbox; > I would like to implement * ITERINDEX* and probably *VOLATILEDIR *but not sure if this is the correct change or if i need to change something into the database. from: password_query = select login as user, crypt_sha1 as password, home as > userdb_home, uid AS userdb_uid, gid AS userdb_gid, > concat(maildir,':INDEX=/data/indexes/',login) as userdb_mail from mailbox > left join aliases on aliases.systemid = aliasid where login = '%u' and > inactive = 0; > to: password_query = select login as user, crypt_sha1 as password, home as > userdb_home, uid AS userdb_uid, gid AS userdb_gid, > concat(maildir,':INDEX=/data/indexes/',login,':ITERINDEX',':VOLATILEDIR=/tmp/%2.256Nu/%u',login) > as userdb_mail from mailbox left join aliases on aliases.systemid = aliasid > where login = '%u' and inactive = 0; > But not sure if is working correctly, * i checked debuging* in my imap node in this way: auth_verbose = yes > auth_verbose_passwords = no > auth_debug = yes > auth_debug_passwords = yes > mail_debug = yes > verbose_ssl = yes > This is the output log: Feb 15 09:32:53 my-imap-server dovecot: auth: Debug: sql(manolo1(a)mydomain,10.X.X.109,<eWEh7bj09N4KAjxt>): cache hit: {SHA}8376922a27e83b9eadcdec3596a70bf6c4db5730#011user=manolo1@mydomain #011userdb_home=/data/mail/tmydomain/users/manolo1#011userdb_uid=700#011userdb_gid=700#011userdb_mail=/data/mail/mydomain/users/manolo1/Maildir/:INDEX=/data/indexes/manolo1@mydomain :ITERINDEX:VOLATILEDIR=/tmp/3a/manolo1@mydomain *Not sure if is correct the output or should i need to change something into the database or this change only afect locally?* 5) *mailbox_list_index = yes ???* Mailbox list indexes can be used to optimize IMAP STATUS commands. They are > also required for IMAP NOTIFY extension to be enabled. > *It is this option necesary to add? in order to work with ITERINDEX option ?* https://www.mail-archive.com/dovecot@dovecot.org/msg75035.html ( i see your answer to this post ) 6) *What is the best way to do a maintenance in a backend?* The last time i flushed all the user in a director from a backend node to do a maintenance, after the maintenance done i rebalanced the director cluster, but the next day when user started tp connect we got high peak I/O , etc with a lot of problems, because new users in this backend node were re-indexes o creating new indexes. *Are there any way to do in a safer way? *Without loosing the hashed for the directors nodes. Thanks in advance!!!!!!!

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