concerning dovecot settings for high volume server
hi
centos 6 64 bit
hex core processor with hyperthreading ie display shows 12 cores 16 gb ram 600 gb 15000 rpm drive
we are having around 4000 users on a server
i wish to allow 1500 pop3 and 1500 imap connections simultaneously.
need help regarding the settings to handle the above
imap-login, pop3-login imap pop3 service settings
i recently i got an error imap-login: Error: read(imap) failed: Remote closed connection (process_limit reached?)
my current dovecot config file
# 2.2.7: /etc/dovecot/dovecot.conf # OS: Linux 2.6.32-431.23.3.el6.x86_64 x86_64 CentOS release 6.5 (Final) auth_cache_negative_ttl = 0 auth_cache_ttl = 0 auth_mechanisms = plain login digest-md5 cram-md5 default_login_user = vpopmail disable_plaintext_auth = no first_valid_gid = 89 first_valid_uid = 89 log_path = /var/log/dovecot.log login_greeting = ready. mail_max_userip_connections = 50 mail_plugins = " quota" managesieve_notify_capability = mailto managesieve_sieve_capability = fileinto reject envelope encoded-character vacation subaddress comparator-i;ascii-numeric relational regex imap4flags copy include variables body enotify environment mailbox date ihave namespace { inbox = yes location = prefix = separator = . type = private } passdb { args = cache_key=%u webmail=127.0.0.1 driver = vpopmail } plugin { quota = maildir:ignore=Trash quota_rule = ?:storage=0 } protocols = imap pop3 service imap-login { client_limit = 256 process_limit = 400 process_min_avail = 4 service_count = 0 vsz_limit = 512 M } service pop3-login { client_limit = 1000 process_limit = 400 process_min_avail = 12 service_count = 0 vsz_limit = 512 M } ssl_cert = </var/qmail/control/servercert.pem ssl_dh_parameters_length = 2048 ssl_key = </var/qmail/control/servercert.pem userdb { args = cache_key=%u quota_template=quota_rule=*:backend=%q driver = vpopmail } protocol imap { imap_client_workarounds = delay-newmail mail_plugins = " quota imap_quota" } protocol pop3 { pop3_client_workarounds = outlook-no-nuls oe-ns-eoh pop3_fast_size_lookups = yes pop3_lock_session = no pop3_no_flag_updates = yes }
thanks very much,
rajesh
You may be running up against Linux system/user limits. Run $ cat /proc/sys/kernel/pid_max and $ ulimit -a That should give some insight into your problem.
On 12/09/2015 2:53 PM, Rajesh M wrote:
hi
centos 6 64 bit
hex core processor with hyperthreading ie display shows 12 cores 16 gb ram 600 gb 15000 rpm drive
we are having around 4000 users on a server
i wish to allow 1500 pop3 and 1500 imap connections simultaneously.
need help regarding the settings to handle the above
imap-login, pop3-login imap pop3 service settings
i recently i got an error imap-login: Error: read(imap) failed: Remote closed connection (process_limit reached?)
my current dovecot config file
# 2.2.7: /etc/dovecot/dovecot.conf # OS: Linux 2.6.32-431.23.3.el6.x86_64 x86_64 CentOS release 6.5 (Final) auth_cache_negative_ttl = 0 auth_cache_ttl = 0 auth_mechanisms = plain login digest-md5 cram-md5 default_login_user = vpopmail disable_plaintext_auth = no first_valid_gid = 89 first_valid_uid = 89 log_path = /var/log/dovecot.log login_greeting = ready. mail_max_userip_connections = 50 mail_plugins = " quota" managesieve_notify_capability = mailto managesieve_sieve_capability = fileinto reject envelope encoded-character vacation subaddress comparator-i;ascii-numeric relational regex imap4flags copy include variables body enotify environment mailbox date ihave namespace { inbox = yes location = prefix = separator = . type = private } passdb { args = cache_key=%u webmail=127.0.0.1 driver = vpopmail } plugin { quota = maildir:ignore=Trash quota_rule = ?:storage=0 } protocols = imap pop3 service imap-login { client_limit = 256 process_limit = 400 process_min_avail = 4 service_count = 0 vsz_limit = 512 M } service pop3-login { client_limit = 1000 process_limit = 400 process_min_avail = 12 service_count = 0 vsz_limit = 512 M } ssl_cert = </var/qmail/control/servercert.pem ssl_dh_parameters_length = 2048 ssl_key = </var/qmail/control/servercert.pem userdb { args = cache_key=%u quota_template=quota_rule=*:backend=%q driver = vpopmail } protocol imap { imap_client_workarounds = delay-newmail mail_plugins = " quota imap_quota" } protocol pop3 { pop3_client_workarounds = outlook-no-nuls oe-ns-eoh pop3_fast_size_lookups = yes pop3_lock_session = no pop3_no_flag_updates = yes }
thanks very much,
rajesh
Am 12.09.2015 um 20:53 schrieb Rajesh M:
hi
centos 6 64 bit
hex core processor with hyperthreading ie display shows 12 cores 16 gb ram 600 gb 15000 rpm drive
we are having around 4000 users on a server
i wish to allow 1500 pop3 and 1500 imap connections simultaneously.
for pop3 you will have no problems, perhaps you need a little tuning imap is different cause many clients will stay idle perhaps you should consider a setup with loadbalancers and more then one servers
Best Regards MfG Robert Schetterer
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Le 12 sept. 2015 à 20:53, Rajesh M a écrit :
hi
[…]
i wish to allow 1500 pop3 and 1500 imap connections simultaneously.
need help regarding the settings to handle the above
imap-login, pop3-login imap pop3 service settings
i recently i got an error imap-login: Error: read(imap) failed: Remote closed connection (process_limit reached?)
[…]
Hello Rajesh,
I guess you could have a look at:
http://wiki2.dovecot.org/ServicesFor example, a pop3 connection requires one pop3-login process and one pop3 process (unless your are running in "high performance mode"; but this doesn’t seem to be the case). So, you would have to adjust the process_limit setting for both of these services.
IIRC, those settings are by default set to 0 and thus take the value of default_process_limit (which in turn defaults to 100).
Of course, as others have already noted, such settings must remain within the limits configured at the system level.
HTH, Axel
Hi,
I have running dovecot with about 28k users. Here comes my relevant config for pop3 and imap from "doveconf -n". No problems so far.
-- snip -- default_client_limit = 2000 ...
service imap-login { inet_listener imap { port = 143 } process_limit = 256 process_min_avail = 50 service_count = 1 } service imap { process_limit = 2048 process_min_avail = 50 service_count = 1 vsz_limit = 512 M } ...
service pop3-login { inet_listener pop3 { port = 110 } process_limit = 256 process_min_avail = 25 service_count = 1 } service pop3 { process_limit = 256 process_min_avail = 25 service_count = 1 } ...
protocol imap { imap_client_workarounds = tb-extra-mailbox-sep imap_id_log = * imap_logout_format = bytes=%i/%o session=<%{session}> mail_max_userip_connections = 40 mail_plugins = " quota mail_log notify zlib imap_quota imap_zlib" }
... protocol pop3 { mail_plugins = " quota mail_log notify zlib" pop3_logout_format = bytes_sent=%o top=%t/%p, retr=%r/%b, del=%d/%m, \ size=%s uidl_hash=%u session=<%{session}> } -- snip --
Regards Urban
Am 12.09.2015 um 20:53 schrieb Rajesh M:
hi
centos 6 64 bit
hex core processor with hyperthreading ie display shows 12 cores 16 gb ram 600 gb 15000 rpm drive
we are having around 4000 users on a server
i wish to allow 1500 pop3 and 1500 imap connections simultaneously.
need help regarding the settings to handle the above
imap-login, pop3-login imap pop3 service settings
i recently i got an error imap-login: Error: read(imap) failed: Remote closed connection (process_limit reached?)
my current dovecot config file
# 2.2.7: /etc/dovecot/dovecot.conf # OS: Linux 2.6.32-431.23.3.el6.x86_64 x86_64 CentOS release 6.5 (Final) auth_cache_negative_ttl = 0 auth_cache_ttl = 0 auth_mechanisms = plain login digest-md5 cram-md5 default_login_user = vpopmail disable_plaintext_auth = no first_valid_gid = 89 first_valid_uid = 89 log_path = /var/log/dovecot.log login_greeting = ready. mail_max_userip_connections = 50 mail_plugins = " quota" managesieve_notify_capability = mailto managesieve_sieve_capability = fileinto reject envelope encoded-character vacation subaddress comparator-i;ascii-numeric relational regex imap4flags copy include variables body enotify environment mailbox date ihave namespace { inbox = yes location = prefix = separator = . type = private } passdb { args = cache_key=%u webmail=127.0.0.1 driver = vpopmail } plugin { quota = maildir:ignore=Trash quota_rule = ?:storage=0 } protocols = imap pop3 service imap-login { client_limit = 256 process_limit = 400 process_min_avail = 4 service_count = 0 vsz_limit = 512 M } service pop3-login { client_limit = 1000 process_limit = 400 process_min_avail = 12 service_count = 0 vsz_limit = 512 M } ssl_cert = </var/qmail/control/servercert.pem ssl_dh_parameters_length = 2048 ssl_key = </var/qmail/control/servercert.pem userdb { args = cache_key=%u quota_template=quota_rule=*:backend=%q driver = vpopmail } protocol imap { imap_client_workarounds = delay-newmail mail_plugins = " quota imap_quota" } protocol pop3 { pop3_client_workarounds = outlook-no-nuls oe-ns-eoh pop3_fast_size_lookups = yes pop3_lock_session = no pop3_no_flag_updates = yes }
thanks very much,
rajesh
participants (5)
-
Axel Luttgens
-
Rajesh M
-
Robert Schetterer
-
Tony Morehen
-
Urban Loesch