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PhoboX

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Hi all

Im new to these forums, but not new to the product. Im using Mailserver 6.1.3 on a Windows 2003 Server machine and Im having problems with the general access speed of the mailserver, either through webmail or via POP. SMTP access and responses seem fine, however I admittedly havent done as much testing on that.

Accessing the server via webmail is extremely slow, but I found it was slightly improved using Firefox. The speed however is still enough for my users to complain about, and I must admit Im not happy with it myself (though Im a lot more tolerant, being a sysadmin and therefore used to things not going quite right). Ive also noticed that connecting via POP is slow, but not nearly as bad as webmail. Downloading messages once connected seems fine however. Is there anything that may explain the slow speed?

I have done network tests to see if the problem was the actual network, no problems there. I have checked all running processes on the server, and nothing seems to be causing a bottleneck or CPU hog, Ive been through the mailserver options and settings time after time, played about a bit but nothing made a difference. Im at a loss as to why this is happening. Its not unusable, but its not right and Im tired of getting complaints from those less tolerant than me.. so I would appreciate any help with this :)

Thanks in advance.
Phobox.

[Updated on: Tue, 10 October 2006 09:42]

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winkelman

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KMS speed is mostly dependant on disk-speed. Best thing would be to use a RAID-10 setup with very speedy 15k RPM SCSI-drives. Of course, if this is not possible, just use the speediest drive-subsystem you can afford.

Oh yes, and keep it defragmented.

But: before going out and spending dollars :) what is your current server spec and are there running more programs on it?
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Dave S

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I'm running KMS on RedHat ES3 (RAID-5/10K RPM disks/120 users) and my system is very fast. Check your network connection between the server and the switch (check the duplex/speed settings on server NIC and SW port and make sure they are in an exact match).

If you are running on Win2k3 Server and it is a fragmentation issue as winkelman suggested, look into purchasing Diskeeper Pro v.10 for auto defragging capabilities. I use it on all my Win32 servers and it is a wonderful product.
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winkelman

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Oh yes, it might help if we mention our specs with no speed problems :)

My system is two SCSI 15k RPM disks in RAID-1. (CPU and memory do not really matter that much for KMW).

This is for ~100 users, all on Webmail, 5 on KOC, 5 on IMAP with about 85 users logged in simultaneously during the day.

I had two occasions when KMS was sluggish. One time the network connection was incorrectly set to Ethernet (10Mbps) instead of Fast-Ethernet (100Mbps) and the other occasion I was running on 7200RPM ATA drives, which was actually too slow.

About defragging: I checked out Diskeeper 10 (excellent program), but found it to be too expensive for my needs. I now defragment the server each night on a quite moment by a batch file that runs the defrag, saves the output and emails it to me (using blat). Works perfect.

[Updated on: Wed, 11 October 2006 15:34]

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PhoboX

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Thanks for the quick responses guys, much appreciated.

I have actually just off-loaded a lot of work from the server box buy purchasing new router hardware and network switches (previously the Win2k3 server was acting as a software router), so this should make life a bit easier for the mailserver because it has a lot more CPU cycles to work with for a start. I am however almost 100% certain its not a server load issue thats causing the speed problems. Network throughput to and from the server is optimal, no problems whatsoever there. I run public webservers as well as the mailserver, and there are no reported speed problems with that at all, and thats all on the same box.

The mailserver does not host many accounts (we're talking low double figures here) and is not all that busy, in fact at any one time there is usually only 1 maybe 2 logins via pop or webmail, easily enough for the current hardware to handle. It gets a fair few SMTP connections from the outside world, but nothing it cant handle, and that seems to be working ok. The only problem is with local logins via POP or webmail, but as previously mentioned its a lot faster via pop, but not as good as it should be.

The server spec is as follows:
AMD Athlon 1900+ at 1.6ghz.
512mb RAM (of which 213 is free, on a good day)
2x 80gb 7200rpm SATA HDD's.
10/100 Realtek NIC
802.11g Wireless NIC
SI2110 RAID SATA

I wont include details of the optical drives and other misc hardware, its not really of any relevence. The spec is nothing compared to those mentioned by you guys, but its enough to handle the fairly small load it currently handles.. and its handled a lot more in the past on larger networks without issue. Im convinced the issue is with Kerio Mailserver itself, rather than caused by hardware or 3rd party software load.. I have no other reported issues with any other services running from this box. One last thing I should mention is that the box does run scheduled defrags via Diskeeper and scheduled anti-virus runs via AVG 7 both on a weekly basis.

Thanks again for the replies and I hope the info I have provided will be of some use.

[Updated on: Wed, 11 October 2006 18:06]

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winkelman

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PhoboX wrote on Wed, 11 October 2006 18:01


AMD Athlon 1900+ at 1.6ghz.
2x 80gb 7200rpm SATA HDD's.
SI2110 RAID SATA

Are you running RAID-0 or RAID-1? Or no RAID at all?
CPU and RAM are certainly no problem. As KMS really is only disk-speed bound, I would still think your problem may lie there. 7200rpm SATA just is pretty slow, even if you only have, say, 25 simutaneous webmail users.

Of course, webmail is a fairly heavy browser app, lot's of javascript. I've noticed it takes at least a >1Ghz machine to run smoothly (it will run OK on sub-1Ghz PC's, but perhaps not as smooth as you'd want).

You could test if it's the client that's too slow by trying the webmail 'mini' interface. Is that also slow?
PhoboX wrote on Wed, 11 October 2006 18:01

and scheduled anti-virus runs via AVG 7 both on a weekly basis.

Since you seem to be new at KMS , some well meant advice:
You should exclude the mail server store directory from the AV scanning. Well, you may perhaps scan the folders, but AVG7 should in no way change the store's contents, so it should not automatically fix or remove found virusses. (It may report found virusses and then you could manually do something about it, ideally through KMS itself.) If programs other then KMS act upon the store, you're bound to end up with index-problems, etc.
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PhoboX

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winkelman wrote on Wed, 11 October 2006 18:25


Are you running RAID-0 or RAID-1? Or no RAID at all?


Not running in a RAID configuration, but the SATA controllers (there are two installed, both of the same chipset, allowing a total of 4 SATA devices and 4 IDE devices to be installed simultaneously) are RAID compatible.

Quote:

Of course, webmail is a fairly heavy browser app, lot's of javascript. I've noticed it takes at least a >1Ghz machine to run smoothly (it will run OK on sub-1Ghz PC's, but perhaps not as smooth as you'd want).

You could test if it's the client that's too slow by trying the webmail 'mini' interface. Is that also slow?


Ive noticed that the primary bottleneck appears to occur during what I call the 'negotiation' phase of accessing webmail. The clients access webmail via secure HTTP, and its very slow to bring up the login screen and relatively slow (but not nearly as much) to actually display the inbox once the user has logged in successfully. Could it be an issue with certificates or the SSL? My hardware may not be great, but I find to difficult to believe it would be directly responsible for the very sluggish response.

Considering sluggish performance is felt with both POP and webmail (both more so just before the login phase rather than actually downloading mail etc) and both are accessed via secure connections, it leads me to believe it could be the security negotiation that KMS has issues with here. Im considering upgrading to the latest version of KMS, do you think that would have an effect?

As for the clients, they are all reasonably high specced machines and none have any network performance issues or other performance related issues, so Im pretty much ruling out those as a cause. I have also noted that accessing webmail is a lot quicker using Firefox rather than IE, is there any particular reason for that?

Lastly I took your advice and reconfigured the weekly AV scan to exclude the store directory and sub-directories.

Thanks in advance.
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winkelman

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Some more ideas:

Webmail can be slow if you set the "Number of displayed messages" (Webmail, Settings, General tab) high. I feel '20' is the best value. (Put it to '200' and it takes here 5 seconds to load a Webmail page.) Of course, now you'll only see 20 messages per page, but searching for messages really should be done through the very fast search box and not by browsing 'through the pages'.

You suspect it might be the SSL. Did you try connecting over normal HTTP? Is that speedier?

Still, the Webmail login screen should just appear instantenous in your browser...
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jshaw541

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We were having very similar issues to you.

KMS is a pretty high performance mail server. You should not be having these issues under normal circumstances.

However, we had a problem awhile back on our KMS box (Windows 2003) and after much work with Kerio engineers, it was determined that an account's mailbox had about a million messages in it and indexing was choking.

You can turn on IMAP traffic for the debug log in the KMS Admin Console. Look for "Saving index" messages with a huge message count. These bog down the server badly. If you find some of these, the solution here is to reduce the messages in such mailboxes.

I urge you to contact Kerio support on this issue, though and see what comes up. If you want to reference my ticket for the Kerio tech's benefit, it's ITS-305744. I don't mind if Kerio shares the information within with you.

I'd also like to add a bit about the SSL issue. I originally thought our issue was due to the fact that we had well over a thousand concurrent SSL connections. This was not the case. SSL, surprisingly, isn't the CPU hog I thought it was.

Again, I think your problem likely lies with index files.

[Updated on: Thu, 12 October 2006 18:49]


Kerio MailServer 6.7.1 w/AD
Windows Server 2003 SP 1
Dell PowerEdge 2850 (Dual Xeon 3.2ghz and 2 GB RAM)
~1300 users
~1000+ concurrent IMAPS connections
iPhone users
Outlook 2007 KOFF users
Apple iCal 10.5/10.6 users
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jdowning

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Here here...add me to the list. KMS performance is dramatically slower on my Server 2003 box than I would expect. To bolster my argument, I place a large file (1GB) on the mail server in a subdirectory. From the KMS website, I can download the file from from home at about 80KB/sec. Then, using an IIS install on the same server, I download the file at 170KB/sec. Twice as fast on IIS?! Something is not write in the webserver build on KMS.

As the previous user stated, I too submitted a ticket (#ZND-671940) with no help with this. I have tested the file download test at several different locations with the same results (KMS slow, IIS 2x fast). I've looked into the message index, but the largest users's mailbox is around 190K items...not close to the million that was reference earlier.

I've started looking into Windows-based diagnositcs or fixes (registry, page file, etc.) but really feel the problems lie with the KMS webserver software, not the physical server it's running on.

BTW, KMS is running virtually alone on Xeon Quad Core 3.0Ghz/4GB RAM/750GB 10K RAID5. Please, can someone help me with this?!

--Justin
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winkelman

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Why are you testing the speed of a MAIL server by downloading large files from it over HTTP (I presume)? You continually refer to KMS as if it where a web server, for example by comparing it with IIS. Why? And what do you mean by 'downloading a large file from KMS'? Does that mean receiving a large email?

Sorry about this, but it's not at all clear to me what you are getting to...
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sedell

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Mail servers aren't designed to transfer 1GB files. When was the last time you sent a 1GB file via e-mail? If you are transferring 1GB files via e-mail, that would explain the slowdown.

Scott
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jdowning

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Okay, fair enough. Mail is NOT a web or file server, but as an application for webmail, KMS is not doing well. Users report undesirable connections via webmail (slow, even on very high speed connections). Even when I log in from the server itself, the interface is slow. Perhaps my expectations are set too high, but an corporate mail server should be one of (if not THE) fastest employee resource. Mine is not. Any suggestions to correct this are much apprecitaed.

--Justin
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sonofcolin

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Webmail speed in 6.4x up has been great. You should compare OWA with Kerio and the tell me which you think is slower. If you are talking about previous versions, then I would agree.

You may also want to compare Firefox / IE / Safari etc. IE is the slowest to load up, but once loaded they all respond the same.
winkelman

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Webmail is very fast here. Only when I run it on an old PC (as in a Pentium II or III) it is a bit slow. But that's to be expected...

I think the server it less of influence then the client in case of Webmail. And besides, your server seems adequate. It would have been faster if you wouldn't have used RAID-5, but I don't think that's the issue here.
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