On 20/06/12 11:40, Angel L. Mateo wrote:
Hello,
I'm migrating from 1.1.16 running in 4 debian lenny servers
virtualized with xenserver and 1 core and 5GB of RAM to 2.1.5 running in
4 ubuntu 12.04 servers with 6 cpu cores and 16GB of RAM virtualized with
VMWare, but I'm having lots a performance problems. I don't think that
virtualization platform could be the problem, because the new servers
running in xenserver has the same problems than running in vmware.
I have about 70000 user accounts, most of them without real
activity (they are students who doesn't read his email or have its
account redirected to other provider). I have about 700-1000 concurrent
imap connections.
I have storage in nfs (nfsv3, the nfs server is a celerra), but
indexes are in local filesystems (each server has its own index fs).
Mailboxes are in maildir format.
Old servers and actual director servers are load balanced with an
radware appdirector load balancer (the new backend servers don't need to
be balanced because I'm using a director farm)
In the old platform I have scenario number 2 described at
http://wiki2.dovecot.org/NFS, but in the new ones I have a director
proxy directing all connections from each user to the same server (I
don't specify any server for the user, director selects it according to
the hash algorithm it has).
Some doubts I have for the recommended in that url:
* mmap_disable: both single and multi server configurations have
mmap_disable=yes but in index file section says that you need it if you
have your index files stored in nfs. I have it stored locally. Do I need
mmap_disable=yes? What it's the best?
* dotlock_use_excl: it is set to no in both configurations, but the
comment says that it is needed only in nfsv2. Since I have nfs3, I have
it set it to yes.
* mail_nfs_storage: In single server is set to no, but in multi server
it set to yes. Since I have a director in front of my backend server,
what is the recommended?
With this configuration, when I have a few connections (about
300-400 imap connections) everything is working fine, but when I
disconnect the old servers and direct all my users' connections to the
new servers I have lot of errors. server loads increments to over 300
points, with a very high io wait. With atop, I could see that of my 6
cores, I have one with almost 100% waiting for i/o and the other with
almost 100% idle, but load of the server is very, very high.
With the old servers, I have performance problems, access to mail
is slow, but it works. But with the new ones it doesn't work at all.
Any idea?
I forgot attaching my doveconf.
--
Angel L. Mateo Martínez
Sección de Telemática
Área de Tecnologías de la Información _o)
y las Comunicaciones Aplicadas (ATICA) / \\
http://www.um.es/atica _(___V
Tfo: 868887590
Fax: 868888337
# 2.1.5: /etc/dovecot/dovecot.conf
# OS: Linux 3.2.0-24-generic x86_64 Ubuntu 12.04 LTS
auth_cache_size = 20 M
auth_cache_ttl = 1 days
auth_debug = yes
auth_master_user_separator = *
auth_verbose = yes
default_process_limit = 1000
disable_plaintext_auth = no
log_timestamp = %Y-%m-%d %H:%M:%S
login_trusted_networks = 155.54.211.176/28
mail_debug = yes
mail_fsync = always
mail_location = maildir:~/Maildir:INDEX=/var/indexes/%n
mail_nfs_storage = yes
mail_privileged_group = mail
maildir_stat_dirs = yes
mdbox_rotate_size = 20 M
passdb {
args = /etc/dovecot/master-users
driver = passwd-file
master = yes
pass = yes
}
passdb {
args = /etc/dovecot/dovecot-ldap.conf.ext
driver = ldap
}
passdb {
args = session=yes dovecot
driver = pam
}
plugin {
lazy_expunge = .EXPUNGED/ .DELETED/ .DELETED/.EXPUNGED/
sieve = ~/.dovecot.sieve
sieve_dir = ~/sieve
sieve_extensions = +imapflags
sieve_max_redirects = 15
zlib_save = gz
zlib_save_level = 6
}
postmaster_address = postmas...@um.es
service anvil {
client_limit = 2003
}
service auth {
client_limit = 3000
unix_listener auth-userdb {
mode = 0666
}
}
service doveadm {
inet_listener {
port = 24245
}
}
service imap {
process_limit = 5120
process_min_avail = 6
vsz_limit = 512 M
}
service lmtp {
inet_listener lmtp {
port = 24
}
process_min_avail = 10
vsz_limit = 512 M
}
service pop3 {
process_min_avail = 6
}
ssl = no
ssl_cert = </etc/ssl/certs/dovecot.pem
ssl_key = </etc/ssl/private/dovecot.pem
userdb {
driver = prefetch
}
userdb {
args = /etc/dovecot/dovecot-ldap.conf.ext
driver = ldap
}
protocol lda {
mail_plugins = " sieve"
}
protocol lmtp {
mail_plugins = " sieve"
}
local 155.54.211.160/27/27 {
doveadm_password = ]dWhu5kB
}
