Hi guys
I have been dealing with this issue for a couple of days, I have this VPS installed with Debian 7 and Virtualmin that worked like a swiss clock since a couple of days ago when the service Dovecot started going down.
Oct 30 19:07:37 vps58163 postfix/smtpd[9538]: connect from host195-246-dynamic.16-87-r.retail.telecomitalia.it[87.16.246.195]
Oct 30 19:07:37 vps58163 postfix/smtpd[9542]: connect from host195-246-dynamic.16-87-r.retail.telecomitalia.it[87.16.246.195]
Oct 30 19:07:37 vps58163 postfix/smtpd[9339]: connect from host195-246-dynamic.16-87-r.retail.telecomitalia.it[87.16.246.195]
Oct 30 19:07:37 vps58163 postfix/smtpd[9544]: connect from host195-246-dynamic.16-87-r.retail.telecomitalia.it[87.16.246.195]
Oct 30 19:07:37 vps58163 postfix/smtpd[9546]: connect from host195-246-dynamic.16-87-r.retail.telecomitalia.it[87.16.246.195]
Oct 30 19:07:37 vps58163 postfix/smtpd[9327]: connect from host195-246-dynamic.16-87-r.retail.telecomitalia.it[87.16.246.195]
Oct 30 19:07:37 vps58163 dovecot: imap-login: Error: auth: connect(login) failed: Cannot allocate memory
Oct 30 19:07:37 vps58163 dovecot: imap-login: Error: auth: connect(login) failed: Cannot allocate memory
Oct 30 19:07:37 vps58163 dovecot: imap-login: Error: connect(ssl-params) failed: Cannot allocate memory
Oct 30 19:07:37 vps58163 dovecot: imap-login: Error: socketpair() failed: Cannot allocate memory
Oct 30 19:07:37 vps58163 postfix/smtpd[9538]: warning: connect to private/tlsmgr: Cannot allocate memory
Oct 30 19:07:37 vps58163 postfix/smtpd[9538]: warning: problem talking to server private/tlsmgr: Cannot allocate memory
Oct 30 19:07:37 vps58163 postfix/smtpd[9542]: warning: connect to private/tlsmgr: Cannot allocate memory
Oct 30 19:07:37 vps58163 postfix/smtpd[9542]: warning: problem talking to server private/tlsmgr: Cannot allocate memory
Oct 30 19:07:37 vps58163 postfix/smtpd[9339]: warning: connect to private/tlsmgr: Cannot allocate memory
Oct 30 19:07:37 vps58163 postfix/smtpd[9339]: warning: problem talking to server private/tlsmgr: Cannot allocate memory
Oct 30 19:07:37 vps58163 postfix/smtpd[9544]: warning: SASL authentication failure: cannot connect to saslauthd server: Cannot allocate memory
Oct 30 19:07:37 vps58163 postfix/smtpd[9544]: warning: SASL authentication failure: Password verification failed
Oct 30 19:07:37 vps58163 postfix/smtpd[9544]: warning: host195-246-dynamic.16-87-r.retail.telecomitalia.it[87.16.246.195]: SASL PLAIN authentication failed: generic failure
Oct 30 19:07:37 vps58163 postfix/smtpd[9327]: warning: connect to private/tlsmgr: Cannot allocate memory
Oct 30 19:07:37 vps58163 postfix/smtpd[9327]: warning: problem talking to server private/tlsmgr: Cannot allocate memory
Oct 30 19:07:37 vps58163 dovecot: imap-login: Fatal: Error reading configuration: net_connect_unix(/var/run/dovecot/config) failed: Cannot allocate memory
Oct 30 19:07:37 vps58163 dovecot: master: Error: service(imap-login): command startup failed, throttling for 2 secs
Oct 30 19:07:37 vps58163 postfix/smtpd[9544]: disconnect from host195-246-dynamic.16-87-r.retail.telecomitalia.it[87.16.246.195]
Oct 30 19:07:37 vps58163 postfix/smtpd[9544]: connect from host195-246-dynamic.16-87-r.retail.telecomitalia.it[87.16.246.195]
Oct 30 19:07:37 vps58163 dovecot: imap-login: Error: net_connect_unix(imap) failed: Cannot allocate memory
Oct 30 19:07:37 vps58163 dovecot: imap-login: Internal login failure (pid=9557 id=1) (internal failure, 1 succesful auths): user=<info.isanmarinoapp>, method=PLAIN, rip=87.16.246.195, lip=92.222.2.87, TLS, session=<0StnwacGSgBXEPbD>
Here is some log’s lines from /var/log/mail.log.
As soon those warnings appear my users cannot log into their email account anymore until I restart the Dovecot service.
This happens 3/4 times a day and it’s a very pain in the ass, I tried to search everywhare without any luck and I really cannot understand what causes this issue.
The message “Cannot allocate memory” it’s very odd because I still have a lot of free resource on this machine.
Eric actually I don’t know if I use OpenVZ, I just installed VirtualMin.
Dustin I don’t know of what kind of memory the warning is talking about because I still have a lot of free space on the hard disk and more than two third of free ram (4gig total).
That particular file does indicate that you’re using OpenVZ.
Everything listed in there is related to your OpenVZ resources.
We’ve seen quite a few unusual resource related issues when using OpenVZ… even if it appears that there is plenty of RAM, if it’s burst RAM that’s being used at the time, that RAM can be taken away to give to other users on the server (that is, burst RAM isn’t guaranteed).
It doesn’t appear RAM related in your case though.
Note the “failcnt” field on the far right of the output you’ve shared above… any failure listed there indicates something that asked for resources and was denied.
In your case, there are over 100 “numothersock” failures.
That parameter refers to the maximum number of non-TCP sockets (local sockets, UDP, and other types of sockets).
Looking at the output you initially shared, it looks like the “numothersock” failures correspond with the errors in your output.
What you may need to do is ask your provider for more resources. More resources altogether is good, but in particular you may want to ask them to increase the “numothersock” value.
Note though that this sort of resource issue is unique to OpenVZ, Xen, KVM, and VMware-based providers don’t use the same method for resource restriction. With other VPS types, it’s just about ensuring that you have enough RAM.
Thank you so much Eric for your answer, so I guess the best way to avoid this kind of issue should be, instead of using a VPS, buy a dedicated server.
I noticed another thing: I logged in into the virtualmin mail interface with root account and there were about 68000 (not kidding) emails from “Cron Deamon” (issue similar to this thread http://www.virtualmin.com/node/30990 ) so as suggested in that thread I deleted all the email and disabled this cron job
The setting your provider is using for numothersock is way too low! Dovecot uses lots of sockets to do its thing, and 500 is way too low, I have 1982 used on a VPS with about 5 users on it. Sockets are an integral part of a Linux system and a limit like that would cause all kinds of chaos!
It should be set to “9223372036854775807” the same as the other counters.
I am not aware of AWstats using any sockets, but I don’t really deal with it much.
