High Load average on NFS Spool - v.2.1.15 & 2.2.13

admin admin at awib.it
Tue Dec 18 21:40:16 EET 2018


Am Dienstag, den 18.12.2018, 14:26 -0500 schrieb Albert E. Whale, CEH
CHS CISA CISSP:
>     I have, but I will be happy to review it once again.
> 
>     
>     On 12/18/18 2:14 PM, admin wrote:
> 
>     
>     
> >       
> >       Am Dienstag, den 18.12.2018, 14:06 -0500 schrieb Albert E.
> >         Whale, CEH CHS CISA CISSP:
> >       
> > >         I have two servers pointing to an NFS mounted mail spool
> > > with
> > >           dovecot.  Since I recently switched from using Dovecot
> > > v1.X, I
> > >           have been experiencing high CPU use with the two
> > > Dovecot
> > >           servers.  I am not certain why they are not well
> > > behaved. 
> > >           Here is the configuration information.
> > >         
> > > 
> > >         
> > >         This configuration is currently running at a load average
> > > of
> > >           17.
> > > 
> > >         
> > >         /usr/sbin/dovecot -n
> > > 
> > >           # 2.1.15: /etc/dovecot/dovecot.conf
> > > 
> > >           # OS: Linux 3.10.54-server-2.mga3 i686 Mageia 3
> > > 
> > >           base_dir = /var/run/dovecot/
> > > 
> > >           disable_plaintext_auth = no
> > > 
> > >           lock_method = dotlock
> > > 
> > >           login_greeting = SpamZapper Email ready.
> > > 
> > >           login_log_format_elements = user=<%u> method=%m rip=%r
> > >           lip=%l %c
> > > 
> > >           mail_debug = yes
> > > 
> > >           mail_fsync = always
> > > 
> > >           mail_location = maildir:~/Maildir
> > > 
> > >           mail_nfs_index = yes
> > > 
> > >           mail_nfs_storage = yes
> > > 
> > >           mail_privileged_group = mail
> > > 
> > >           mbox_lock_timeout = 15 mins
> > > 
> > >           mmap_disable = yes
> > > 
> > >           passdb {
> > > 
> > >             driver = pam
> > > 
> > >           }
> > > 
> > >           protocols = imap pop3
> > > 
> > >           service anvil {
> > > 
> > >             client_limit = 203
> > > 
> > >             process_limit = 1
> > > 
> > >           }
> > > 
> > >           service auth {
> > > 
> > >             user = root
> > > 
> > >           }
> > > 
> > >           service imap-login {
> > > 
> > >             chroot = login
> > > 
> > >             client_limit = 10
> > > 
> > >             user = dovecot
> > > 
> > >             vsz_limit = 256 M
> > > 
> > >           }
> > > 
> > >           service pop3-login {
> > > 
> > >             chroot = login
> > > 
> > >             client_limit = 20
> > > 
> > >             user = dovecot
> > > 
> > >           }
> > > 
> > >           ssl = no
> > > 
> > >           syslog_facility = local2
> > > 
> > >           userdb {
> > > 
> > >             driver = passwd
> > > 
> > >           }
> > > 
> > >           verbose_proctitle = yes
> > > 
> > >           protocol pop3 {
> > > 
> > >             mail_max_userip_connections = 20
> > > 
> > >             pop3_logout_format = top=%t/%p, retr=%r/%b,
> > > del=%d/%m,
> > >           size=%s
> > > 
> > >             pop3_uidl_format = %08Xv%08Xu
> > > 
> > >           }
> > > 
> > >           protocol lda {
> > > 
> > >             postmaster_address = postmaster at example.com
> > > 
> > >           }
> > > 
> > >           protocol imap {
> > > 
> > >             mail_max_userip_connections = 10
> > > 
> > >           }
> > > 
> > >         
> > >         And the other server which is currently running with a
> > > load
> > >           average of 10.
> > >         dovecot -n
> > > 
> > >           # 2.2.13: /etc/dovecot/dovecot.conf
> > > 
> > >           doveconf: Warning: service anvil { client_limit=100 }
> > > is lower
> > >           than required under max. load (303)
> > > 
> > >           # OS: Linux 4.1.15-server-2.mga5 x86_64 Mageia 4
> > > 
> > >           base_dir = /var/run/dovecot/
> > > 
> > >           disable_plaintext_auth = no
> > > 
> > >           listen = *
> > > 
> > >           lock_method = dotlock
> > > 
> > >           login_greeting = SpamZapper Email ready.
> > > 
> > >           login_log_format_elements = user=<%u> method=%m rip=%r
> > >           lip=%l %c
> > > 
> > >           mail_fsync = always
> > > 
> > >           mail_location = maildir:~/Maildir
> > > 
> > >           mail_nfs_index = yes
> > > 
> > >           mail_nfs_storage = yes
> > > 
> > >           mail_privileged_group = mail
> > > 
> > >           mmap_disable = yes
> > > 
> > >           passdb {
> > > 
> > >             driver = pam
> > > 
> > >           }
> > > 
> > >           protocols = imap pop3
> > > 
> > >           service anvil {
> > > 
> > >             client_limit = 100
> > > 
> > >             process_limit = 1
> > > 
> > >           }
> > > 
> > >           service auth {
> > > 
> > >             user = root
> > > 
> > >           }
> > > 
> > >           service imap-login {
> > > 
> > >             chroot = login
> > > 
> > >             client_limit = 48
> > > 
> > >             user = dovecot
> > > 
> > >             vsz_limit = 256 M
> > > 
> > >           }
> > > 
> > >           service pop3-login {
> > > 
> > >             chroot = login
> > > 
> > >             client_limit = 50
> > > 
> > >             user = dovecot
> > > 
> > >           }
> > > 
> > >           ssl = no
> > > 
> > >           syslog_facility = local2
> > > 
> > >           userdb {
> > > 
> > >             driver = passwd
> > > 
> > >           }
> > > 
> > >           verbose_proctitle = yes
> > > 
> > >           protocol pop3 {
> > > 
> > >             mail_max_userip_connections = 50
> > > 
> > >             pop3_logout_format = top=%t/%p, retr=%r/%b,
> > > del=%d/%m,
> > >           size=%s
> > > 
> > >             pop3_uidl_format = %08Xv%08Xu
> > > 
> > >           }
> > > 
> > >           protocol lda {
> > > 
> > >             postmaster_address = postmaster at example.com
> > > 
> > >           }
> > > 
> > >           protocol imap {
> > > 
> > >             mail_max_userip_connections = 40
> > > 
> > >           }
> > > 
> > >         
> > >         Can you please offer a suggestion on what is happening? 
> > > The
> > >           timeouts to the imap server are frequent due to the
> > > load
> > >           average.
> > >         Thank you.
> > > 
> > >         
> > >         -- 
> > > 
> > >           -- 
> > > 
> > >           --
> > > 
> > >           
> > > 
> > >           Albert E. Whale, CEH CHS CISA CISSP
> > > 
> > >           President - Chief Info Security Officer
> > > 
> > >           IT Security, Inc. - A Service
> > >           Disabled Veteran Owned Company - (SDVOSB)
> > > 
> > >           HUBZone Certified
> > > 
> > >           LinkedIn Profile
> > > 
> > >           
> > > 
> > >           
> > > 
> > >           Phone: 412-515-3010 | Email: 
> > > Albert.Whale at IT-Security-inc.com
> > > 
> > >           Cell: 412-889-6870
> > > 
> > >           
> > > 
> > >         
> > >       
> > 
> >       
> > 
> >       
> >       Did  you have a look at https://wiki2.dovecot.org/NFS
> >         ?
> >       
> > 
> >       
> >       -- 
> >       
> >           awib IT Solutions
> >           info at awib.it
> > 
> >         
> >     
> 
>     -- 
> 
>       -- 
> 
>       --
> 
>       
> 
>       Albert E. Whale, CEH CHS CISA CISSP
> 
>       President - Chief Info Security Officer
> 
>       IT Security, Inc. - A
>       Service Disabled Veteran Owned Company - (SDVOSB)
> 
>       HUBZone Certified
> 
>       LinkedIn
>       Profile
> 
>       
> 
>       
> 
>       Phone: 412-515-3010 | Email: Albert.Whale at IT-Security-inc.com
> 
>       Cell: 412-889-6870
> 
>       
> 
>     
>   
> 

Please try to bottom post.
Would be interesting to know what causes the load (which is not
restricted to be caused by CPU only!):

https://unix.stackexchange.com/a/130970

Might NFS be the culprit?
https://serverfault.com/a/120874/229525

-M-- 
awib IT Solutionsinfo at awib.it
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