HI All,
We have a couple of dovecot director proxies and six backed mailstores
each accessing mailboxes stored on five NFSv4 filsystems with about
1TB of mail on each in maildir format.? We have about 800 max users
on each mailstore at peak times and performance appears to starting to
degrade at these times.? The mailstores are pretty recent hardware
with 64GB of RAM and 24 cores.?? The NFS storage is EMC VNX and we
are doing about 250 I/O per sec upto max of 500 on each
filesystem.?? I need to squeeze more performance out of these
servers whether that is in the NFS client, Dovecot or Linux OS/kernel
areas.?? We use LDAP for auth and I am doing some tuning in that
area.?? The NFS filesystems are mounted with the options below:
10.11.0.238:/mailbox_store_01 on /home1 type nfs4
(rw,relatime,vers=4.0,rsize=65536,wsize=65536,namlen=255,hard,nordirplus,proto=tcp,port=0,timeo=600,retrans=2,sec=sys,clientaddr=10.11.0.96,local_lock=none,addr=10.11.0.238)
My dovecot config is below.? I am not seeing any obvious issues in
the server logs.??? Any suggestions on how to improve performance
would be appreciated.
Thanks
Murray
# doveconf -n
# 2.2.9: /etc/dovecot/dovecot.conf
doveconf: Warning: service auth { client_limit=40960 } is lower than
required under max. load (41280)
doveconf: Warning: service anvil { client_limit=40970 } is lower than
required under max. load (41183)
# OS: Linux 3.13-0.bpo.1-amd64 x86_64 Debian 7.5
auth_cache_size = 64 M
auth_cache_ttl = 2 hours
auth_failure_delay = 0
auth_mechanisms = plain login
auth_username_chars
"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789!#$-=?^_{}~./@+%"
auth_username_translation = +@
auth_worker_max_count = 256
base_dir = /var/run/dovecot/
disable_plaintext_auth = no
first_valid_gid = 1001
first_valid_uid = 1001
mail_fsync = always
mail_location = maildir:~/
managesieve_notify_capability = mailto
managesieve_sieve_capability = fileinto reject envelope
encoded-character vacation subaddress comparator-i;ascii-numeric
relational regex imap4flags copy include variables body enotify
environment mailbox date ihave
mmap_disable = yes
namespace {
? inbox = yes
? location ? prefix = INBOX.
? type = private
}
passdb {
? args = /etc/dovecot/dovecot-ldap.conf.ext
? driver = ldap
}
plugin {
? acl = vfile
? quota = maildir
? quota_rule = INBOX.Trash:ignore
}
protocols = " imap lmtp sieve pop3"
service anvil {
? client_limit = 40970
}
service auth-worker {
? user = dovecot
}
service auth {
? client_limit = 40960
? unix_listener auth-userdb {
??? group = mail
??? mode = 0666
??? user = dovecot
? }
}
service imap-login {
? chroot = login
? inet_listener imap {
??? address = *, [::]
??? port = 143
? }
? inet_listener imaps {
??? address = *
??? port = 993
??? ssl = yes
? }
? process_limit = 20480
? process_min_avail = 32
? service_count = 1
? user = dovecot
? vsz_limit = 256 M
}
service imap {
? process_limit = 40960
? vsz_limit = 256 M
}
service lmtp {
? inet_listener lmtp {
??? address = 27.54.95.41
??? port = 24
? }
? process_min_avail = 32
}
service managesieve-login {
? client_limit = 40960
? process_limit = 120
? process_min_avail = 5
? service_count = 0
? vsz_limit = 64 M
}
service managesieve {
? process_limit = 4096
? vsz_limit = 256 M
}
service pop3-login {
? chroot = login
? inet_listener pop3 {
??? address = *, [::]
??? port = 110
? }
? inet_listener pop3s {
??? address = *
??? port = 995
??? ssl = yes
? }
? process_limit = 20480
? process_min_avail = 32
? service_count = 1
? user = dovecot
? vsz_limit = 256 M
}
service pop3 {
? process_limit = 40960
? vsz_limit = 256 M
}
ssl_cert =
On 22 Jul 2014, at 04:57, Murray Trainer <mtrainer at westnet.com.au> wrote:> We have a couple of dovecot director proxies and six backed mailstores > each accessing mailboxes stored on five NFSv4 filsystems with about > 1TB of mail on each in maildir format. We have about 800 max users > on each mailstore at peak times and performance appears to starting to > degrade at these times. The mailstores are pretty recent hardware > with 64GB of RAM and 24 cores. The NFS storage is EMC VNX and we > are doing about 250 I/O per sec upto max of 500 on each > filesystem. I need to squeeze more performance out of these > servers whether that is in the NFS client, Dovecot or Linux OS/kernel > areas. We use LDAP for auth and I am doing some tuning in that > area. The NFS filesystems are mounted with the options below: > > 10.11.0.238:/mailbox_store_01 on /home1 type nfs4 > (rw,relatime,vers=4.0,rsize=65536,wsize=65536,namlen=255,hard,nordirplus,proto=tcp,port=0,timeo=600,retrans=2,sec=sys,clientaddr=10.11.0.96,local_lock=none,addr=10.11.0.238)Does relatime work with NFS? If yes, changing it to noatime would save some I/O. maildir_very_dirty_syncs=yes should be helpful.> # 2.2.9: /etc/dovecot/dovecot.confmailbox_list_index=yes might be useful, although it has had some further performance improvements since v2.2.13. I should try to make v2.2.14 soon..> quota = maildirDict file quota would be a bit faster than maildir++ quota.