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://wiki.dovecot.org/PerformanceTuning> ,
https://doc.dovecot.org/configuration_manual/nfs/
<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 <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
<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
<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@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
<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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