hMailServer hangs under "heavy" load

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sergej69
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hMailServer hangs under "heavy" load

Post by sergej69 » 2014-07-03 13:54

I setup hMailServer for your business application needs. We used IIS SMTP/POP3 before but how we moved to Windows 2008 server we need POP3 alternative.
hMailServer SMTP/POP3 perfectly satisfy our needs, but as it looks like, we have a problem under conditions when several SMTP sessions is triggered from several business application servers simultaneously.
I have setup maximum number of simultaneous SMTP connections to 1000. Under conditions when several of our application servers start to trigger SMTP sessions/connections to hMailServer simultaneous, hMailServer hangs. When maximum number of simultaneous SMTP connections is set to 0 (unlimited), hMailServer hangs as well.

Before we replaced MS IIS SMTP/POP3 with hMailServer, we didn't have any problems.

Any similar experiences or suggestions?

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Re: hMailServer hangs under "heavy" load

Post by sergej69 » 2014-07-03 14:45

Regarding my previous post ... just to mention:
hMailServer Anti-spam and Antivirus scanning is disabled and hMailServer folders are excluded from antivirus protection

Thanks in advance

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Re: hMailServer hangs under "heavy" load

Post by ^DooM^ » 2014-07-03 20:03

Are you logging into a single pop3 account with multiple applications?

Have you set the connecting IP range for your internal ip's up to have a priority over 20?
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sergej69
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Re: hMailServer hangs under "heavy" load

Post by sergej69 » 2014-07-04 08:42

> Are you logging into a single pop3 account with multiple applications?

no, we have several pop3 account under several (four) Domains

> Have you set the connecting IP range for your internal ip's up to have a priority over 20?

We have two IP ranges, default one "My Computer" 127.0.0.1 - 127.0.0.1 with Priority 10 and the other one for our internal IPs with Priority 10.

How IP range priority affects?
I have to point out that in described situation hMailServer become totaly unresponsive and have to be restarted

Thank you in advance

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Re: hMailServer hangs under "heavy" load

Post by mattg » 2014-07-04 10:40

all being priority 10 means that the first alphabetically get s used.

Priority should be >20 (say 25) for all ranges that you don't want affected by autoban.
Highest number is highest priority


What are the hardware specs of this server?
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https://www.hmailserver.com/documentation

sergej69
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Re: hMailServer hangs under "heavy" load

Post by sergej69 » 2014-07-04 11:36

Server is VMware virtualized:

CPU: 2x Quad-Core AMD Opteron 2,5GHz
RAM: 6GB
HD: 10GB+40GB
Eth.: 1Gb

Windows Server 2008 R2 Enterprise SP1 64-bit

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Re: hMailServer hangs under "heavy" load

Post by ^DooM^ » 2014-07-04 21:04

Set th epriority up on that internal range to 25 and let us know how you get on.
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Re: hMailServer hangs under "heavy" load

Post by sergej69 » 2014-07-08 10:58

hi
we set the priority as you suggested and we done some tests in last days, and hMailServer hanged again
We repeated the same test several times. In this test we produced stream of several thousand SMTP messages (simple text) with 5 different and independent java applications. hMailServer should accept generated messages and forward them to another SMTP server.
In all the tests carried out successfully, hMailServer SMTP successfully accepted produced SMTP messages in its delivery queue, but as it seems sometimes it has a problem by proceeding them forward.
By some repeats hMailServer failed to forward accepted messages. It hanged in some points after accepting all generated messages. At that point hMailServer CPU usage shows 25%, SMTP over telnet is not available any more, accepted messages remain in delivery queue, enabled logging is stopped, POP3 mailboxes are not accessible. hMailServer have to be restarted!

Any idea?

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Re: hMailServer hangs under "heavy" load

Post by agserna » 2014-07-08 12:38

Hy

I had a similar problem day's ago

One account was used to send spam (stolen credentials) and HMS crashed with about 500.000 messages (3/4 recipients each) in queue

In my case the hang was caused by the script (in eventhandler) that should had limit the number of sent messages.

So check if you have similar scripts in eventhandler file.

Hope this may help.

Bye

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Re: hMailServer hangs under "heavy" load

Post by sergej69 » 2014-07-08 12:45

we don't use any event scripts and every line in EventHandlers.vbs is marked as comment

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Re: hMailServer hangs under "heavy" load

Post by mattg » 2014-07-08 16:25

Where is the mail being forwarded to?
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Re: hMailServer hangs under "heavy" load

Post by sergej69 » 2014-07-09 09:20

simple, just for test, to another SMTP

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Re: hMailServer hangs under "heavy" load

Post by mattg » 2014-07-09 15:12

local or internet based?
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Re: hMailServer hangs under "heavy" load

Post by sergej69 » 2014-07-09 15:32

local

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Re: hMailServer hangs under "heavy" load

Post by mattg » 2014-07-09 15:58

Is that other SMTP server able to keep up?

What size messages are you sending?
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Re: hMailServer hangs under "heavy" load

Post by sergej69 » 2014-07-10 12:49

messages are simple text less than 1kb,
SMTP at destination server can handle mail without any problem,

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Re: hMailServer hangs under "heavy" load

Post by Rod1 » 2014-07-10 12:58

I'm not an expert so not sure if this post will help...
We just setup hmail last week it was on a server with TrendMicro Server and Client installed and running as a secondary domain controller. For the first few days it was struggling on regular occasions, on the outlook clients send was ok but receive seem to be wiping its feet a lot, kind of hanging and then releasing or maybe not, each time I went to hmail it had locked up and had to reboot (most time when rebooting got message explore.exe was not responding). We moved hmail onto a Std Win7 PC without anything else on it a few days ago and it's been fine since then no problems at all.

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Re: hMailServer hangs under "heavy" load

Post by Bill48105 » 2014-07-11 17:38

Not sure if it'll help but there are know problems with the official releases due to race conditions in the code. I believe I have it fixed in my experimental builds but the changes have not made it into official hmail code yet. You might try my build & see if it helps.
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