[Dovecot] Calculation of suggested vsz_limit values

[Nikolaos Milas]

Hi,

No hints about vsz_limit values?

Anyone?

Thanks,
Nick

On 16/12/2011 11:09 πμ, Nikolaos Milas wrote:

> Hello,
>
> I would like to ask on suggested vsz_limit values.
>
> Is there any way of calculating such values? How should we determine 
> them? I don't want to risk wrong values (and possible errors) on a 
> production system, if I upgrade to 2.0.16 where vsz_limit values are 
> enforced (I read release notes)!
>
> If there is no standard way of calculation, could someone please check 
> the following info and suggest some values?
>
> I am running dovecot-2.0.13-1_128.el5 x86_64 RPM on CentOS 5.7 (as a 
> VM on a KVM Host).
>
> All accounts are virtual, hosted on LDAP Server. We have about 250 
> mailboxes of 4GB each (in practice, only a couple of mailboxes ever 
> reach 1GB so we are "over-booking"). It is a relatively low-load server.
>
> Memory status and config follows below.
>
> Thanks,
> Nick
>
> The server memory condition is as follows:
>
> # vmstat
> procs -----------memory---------- ---swap-- -----io---- --system-- 
> -----cpu------
>  r  b   swpd   free   buff  cache   si   so    bi    bo   in   cs us 
> sy id wa st
>  0  0     92  62400 212324 1299604   0    0   397   235   70   39  4  
> 2 89  4  0
>
> # free -m
>              total       used       free     shared    buffers     cached
> Mem:          2010       1951         59          0        207       1269
> -/+ buffers/cache:        474       1536
> Swap:         2015          0       2015
>
> ---------- Config Start -------------
>
> # 2.0.13: dovecot.conf
>
> protocols = imap pop3
>
> mail_location = maildir:~/Maildir/
> mail_gid = 500
> mail_uid = 500
>
> auth_mechanisms = plain login
> auth_username_format = %Lu
> auth_verbose = yes
> disable_plaintext_auth = no
>
> mail_plugins = quota
>
> protocol imap {
>   imap_client_workarounds = "delay-newmail  "
>   mail_plugins = quota imap_quota
> }
>
> protocol pop3 {
>   mail_max_userip_connections = 3
>   mail_plugins = quota
>   pop3_client_workarounds = outlook-no-nuls oe-ns-eoh
>   pop3_uidl_format = %08Xu%08Xv
> }
>
> protocol lda {
>   auth_socket_path = /var/run/dovecot/auth-master
>   info_log_path =
>   log_path =
>   mail_plugins = quota
>   postmaster_address = sysadmin at example.com
>   sendmail_path = /usr/lib/sendmail
> }
>
> userdb {
>   args = /etc/dovecot/dovecot-usrdb-ldap.conf
>   driver = ldap
> }
>
> passdb {
>   args = /etc/dovecot/dovecot-passdb-ldap.conf
>   driver = ldap
> }
>
> plugin {
>   quota = maildir:User quota
>   quota_rule = *:storage=4G
>   quota_rule2 = Trash:storage=+3%%
>   quota_warning = storage=75%% quota-warning 75 %u
>   quota_warning2 = storage=90%% quota-warning 90 %u
> }
>
> service quota-warning {
>   executable = script /opt/mail1.sh
>   user = vmail
>   unix_listener quota-warning {
>     user = vmail
>   }
> }
>
> service auth {
>   unix_listener /var/spool/postfix/private/auth {
>     group = postfix
>     mode = 0660
>     user = postfix
>   }
>   unix_listener auth-master {
>     group = vmail
>     mode = 0660
>     user = vmail
>   }
>   user = root
> }
>
> service imap-login {
>   service_count = 1
>   vsz_limit = 64 M
> }
>
> service pop3-login {
>   service_count = 1
>   vsz_limit = 64 M
> }
>
> ssl_ca = </etc/pki/CA/certs/chain.pem
> ssl_cert = </etc/pki/CA/certs/cert.pem
> ssl_key = </etc/pki/CA/private/key.pem
>
> syslog_facility = local1
>
> ---------- Config End -------------
>
>