AMS freezing up

[DTower5]

Hi,

I'm in the middle of a pickle and can't find the problem - currently AMS is freezing up quite often. It was freezing up completely, not accepting SMTP connections, webmail etc,

I switch from service to App same problem, upgraded from 2.61 to 2.62, same problem, have tried limiting the connections, same problem.

I am not sure what is going on - multiple reboots, switching from manual startup to service, changing around domains from enabled to disabled, and nothing is solving this.

Right now its doing a partial freeze, the status meter which shows hong long it is running will freeze for a couple of minutes. I have task manager running when this happens and don't see any abnormal things (mem normal and cpu is below 30% utilized)

I'm going nuts because this setup has been working perfect for years, but this morning just started going bonkers.

[rob]

Sorry to hear about your problem, what I can recommend is that you try rebooting the computer firstly and ensuring any network drivers are up to date. Also, if the computer has a firewall or AV scanner installed and you can accept the risk, try temporarily disabling those. If the problem persists and the freezes are frequent enough, then try disabling individual services such as POP3, IMAP4, WebMail and POP3 Retrievals, then monitoring the mail server to see if the problem goes away. This will allow you to wittle it down to which service is at fault. Of course this will cause problems for certain users but the freezes sound similarly quite bad anyway. A solution which can work with this type of problem but isn't usually an option is to simply move the mail server onto another server.

[fiver]

I occassionally have had the same problem. When looking at the logs I found that my outmail and SMTP were renewing at the rate of once every minute and that there was a lot of unexplained e-mail goung through outmail and the SMTP. Despite having SMTP authentication enabled (See post re SMTP authentication) and the Spam filter to exclude locally accounts it appeared that lost of other rubbish was still going through my server.

RBL's did not help but I have now tried the Bayesian filters - Waiting to see what happens.

[DTower5]

I was able to fix the problem (fix) by limiting my outbound connections to 3 and my webmail connections to 200. It slows down mail delivery, but I would rather have that than no mail at all. Soon I switch it over to a backup box and see if it is the hardware starting to slow down.

[THX_1138]

I find that when this sort of thing happens to us its normally high volumes of spam traffic. They put a strain on the smtp and outgoing mail service. We normally do a search for the worst source of spamming and attempt to block it. Server stability normallly returns after we have stemmed the flow.

Jay

[sillyme]

Just had a similar problem on my server. Was about to move to another box and found that the temp wa high on the CPU. It might run for hours then once it got under a load the temp would increase and it would reboot. A good cleaning adn new heatsink grease lowered the temp by 25C. It has not rebooted since. (the heatsink was the type that use the heat tape and it had become brittle)

[NicholasN]

AMS has been freezing every few days for at least the last 6 months for us. We changed servers adjusted the maximum connections but no luck. Even with just a handfull of connections it will freeze up once every few days. We have a script that checks the POP/SMTP every 5 minutes and if it doesn't respond it kills the process and retarts the service. Not the best way to do things but only solution for now. We are just hopping for the next release to fix the problem or we'll have to buy and convert everything to another mail server software. If I had to take a guess, the problem occurs when an email with a certain type of attachment comes through and AMS can not decode it and gets's stack. If anyone has any ideas please share. thanks.

[sillyme]

If you can identify the attachment that is causing the problem send it to Chris or someone at codecrafters. I am sure they will want to fix it. Better to identify the problem than to just hope the fix is in the next release.

[Code Crafters]

As sillyme suggested, if possible send an example email containing the attachment to chris@code-crafters.com and I'll investigate what could be causing the crash and try to fix it for you.

[NicholasN]

I think I'm getting closer in figuring the freezing problem. It may have to do with IMAP when syncing with clients that have a lot of emails. Anyone else has any info?
Thanks.

[Code Crafters]

If you can manage to successully reproduce the problem everytime then hopefully I can set up a test environment to reproduce and debug the problem and hopefully solve whatever is going wrong for you with this.

[HVGS]

We have had issues with Ability Mail crashing for over 2 years now. I believe it is IMAP as well. We have to run a custom program to keep Ability "alive". Every 30 seconds it checks that IMAP is alive and if it is down for more than 3 consecutive attempts then we restart the program. This is the only way we are surviving with it. We have over 1000 users. Most use webmail.......but we also have over 120 concurrent imap connections.

Sometime we get a week or so without a crash and sometimes we might get 3 crashes in 10 minutes. Makes it very hard to track down.

We have moved the mail server to completely different hardware and operating systems but this doesn't help.

V3 has been promised for so long and I hope it fixes the problem.

Phil

[Code Crafters]

Version 3 will have a serice monitor which will automatically restart any services that stop responding or crash meaning that the services will always be available even after a crash.

We haven't had any other reports of regular crashing but obviously your server sounds to be under quite heavy load which with more activity is more likely to find any bugs that may be in IMAP4 or other parts of the software. As I said, any bugs we can reproduce and pin down we can debug and fix so any information you think might help in reliably triggering the problem would help us to hopefully eliminate the cause of the problem.

[NicholasN]

I think version 2.63 fixed it! I believe the problem was as orginaly thought...IMAP causing the freeze up. With the fixes in 2.63 for the IMAP everything seems to be working perfectly now..3 days and counting. Thanks Chris!

[Code Crafters]

It can take a long time via IMAP4 to manage folder headers in outlook etc when many mails are present because each mail header is sometimes downloaded to resynchronise. We recommend you archive mails into another folder (e.g. "Old Mails") so that your Inbox isn't as full when accessed regularly to speed things up. Although taking a while on the client this shouldn't freeze AMS but will take a bit of processing. Make sure you don't have any antivirus scanning going on in the background (not including AMS integrated antivirus of course). If you have a very busy mail server maybe you need to upgrade the hardware to cope with this (e.g. more RAM) but it doens't normally take a very high end dedicated PC to run a mail server, even a busy one.