Hi all,

Over the past week our mail server which NFS mounts the /home directory for mail has been experiencing major load issues. When doing a 'top', it appeared that slapd was the culprit (we use LDAP for authentication), but after upgrading the system and updating ldap, the cpu usage for LDAP has gone down, but the load average as not.

I'm using Maildir. Everything from /home is NFS mounted, and the structure looks like this:

/home/USERNAME/Maildir

We're doing about 300 email messages a minute right now to that server, which isn't that much.

I'm at a loss of words right now as I do not know where to troubleshoot from here. I've come up with the following questions:

1. I've noticed that some of our users have 500mb Maildir folders some even have 3gb+ - would this cause the CPU to have such a high load?

2. Currently on the box there is about 120 POP3 connections and 40 IMAP connections. Could this be the issue?

3. When I first set up this server, I appended INDEX=MEMORY to the end of the mail_location line. Should I remove this? I wanted to either remove it or put it on the local machine to speed things up.

Here is my config:

##################### protocols = imap imaps pop3 pop3s listen = * disable_plaintext_auth = no log_path = /var/log/dovecot.log ssl_disable = no ssl_cert_file = /usr/share/ssl/xyz.com/xyz.com.crt ssl_key_file = /usr/share/ssl/xyz.com/xyz.com.key login_dir = /var/run/dovecot-login login_user = dovecot login_process_size = 64 login_process_per_connection = yes login_max_processes_count = 128 login_max_connections = 256 mail_location = maildir:/home/%u/Maildir:INDEX=MEMORY mmap_disable = yes fsync_disable = yes first_valid_uid = 200 maildir_copy_with_hardlinks = yes maildir_copy_preserve_filename = yes

protocol imap { imap_client_workarounds = outlook-idle delay-newmail }

protocol pop3 { pop3_no_flag_updates = no pop3_lock_session = no pop3_uidl_format = %08Xu%08Xv pop3_client_workarounds = }

protocol lda { fsync_disable = no postmaster_address = postmaster@xyz.com hostname = mail.xyz.com }

auth_username_chars = abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ01234567890.-_@ auth_username_format = %Lu auth_verbose = yes auth_worker_max_count = 30

auth default { mechanisms = plain login

passdb pam { args = blocking=yes }

userdb passwd { }

user = dovecot-auth

socket listen { client { path = /var/spool/postfix/private/auth mode = 0660 user = postfix group = postfix } } }

dict { }

plugin { } #####################

Again, this only happened within the past 1-2 weeks.

How can I fix? Thanks in advance!

Patrick