[Dovecot] Configuration advices for a 50000 mailboxes server(s)

[Mauricio López Riffo]

Jan,

>>  How do you measure "concurrent" POP3 users?

We use cacti for metrics like concurrent connections or pop3 delay and 
Zabbix for alarms.

>>  What mailbox-format are you using? Do you have a director, or accounts
>>  sticky to a server some other way?

Maildir like a mailformat and currently without a director, but we 
testing a new environment with director to reduce number of servers (7 
virtual servers with 4 Vcpu, 6gb ram)  At the meantime a lvs piranha do 
the work of steaky connections but its not enought, for this reason will 
use a director.

 >>  How's the NFS performance? I've always bean weary that NFS works 
terribly with many small files (i.e. maildir)..

At peak hours our storage traffic about 10 thousend total ops (bewten 
read and write, 80/20) and cpu mark 70% of use.

>>  What does the metrocluster give you? Is it for disaster recovery on
>>  second location, or do you have two active locations working against the
>>same filesystem?

Our storage have two missions, first hight availability because we have 
two datacenter (environment N +1) and posibility of use two storages in 
cluster for the same filesystems en this two datacenters (Vmware and 
Mail storage resides in NFS filesystem)

>>  Very interesting config. We're close to 1M accounts, GPFS cluster fs, LDAP,
>>  RHEL5/6 and postfix + dovecot director for pop/imap/lmtp,  and moving from
>>  maildir to mdbox.

1M = 1 milion ?  How many servers you have?  hardware?

Any help o contribution, you welcome :)

Regards



El 17-04-2012 9:42, Jan-Frode Myklebust escribió:
> On Tue, Apr 17, 2012 at 08:54:15AM -0300, Mauricio López Riffo wrote:
>>      Here we have approx. 200K users with 4000 concurrent connections
>> (90% POP3 users)
> How do you measure "concurrent" POP3 users?
>
>> All servers in virtual environment Vmware,
>> supermicro servers and Netapp Metrocluster storage solutions (nfs
>> storage with 10G ethernet network)  POP3 sessions take betwen 40 and
>> 300 milisecons at connect, auth and list.  All accounts lives in
>> LDAP, CentOS 5 and exim like a mta relay.
> Very interesting config. We're close to 1M accounts, GPFS cluster fs, LDAP,
> RHEL5/6 and postfix + dovecot director for pop/imap/lmtp,  and moving from
> maildir to mdbox.
>
> What mailbox-format are you using? Do you have a director, or accounts
> sticky to a server some other way?
>
> How's the NFS performance? I've always bean weary that NFS works
> terribly with many small files (i.e. maildir)..
>
> What does the metrocluster give you? Is it for disaster recovery on
> second location, or do you have two active locations working against the
> same filesystem?
>
>
>    -jf

-- 
Mauricio López Riffo
Red Hat Certified Engineer
804006455319519
Administrador de Servicios Internet
Área Ingeniería
Gtd Internet S.A.
http://www.grupogtd.com/
Moneda 920, Oficina 602 - Fono : +562 4139742