[ngw] Spreading the IMAP/POP load

Fri Apr 9 04:00:12 UTC 2010

That's pretty much what we ended up doing.  However, the project came with some built-in stumbling blocks.  I set up a Windows GWIA with a cert for POP and another one for IMAP.  However, since we're still not using Internet Addressing the IMAP gave us the wrong reply-to address for internal correspondents.  So we had to move them back to our original NetWare GWIA which didn't exhibit that behavior.  It also seemed that a newly created/installed NetWare GWIA didn't behave the same way our original did.  So we ended up cloning the original to a WMWare machine and then cloned that into a another one which I then managed to shoehorn into the system.  I had trouble with the server names in the cert we'd worked out but eventually I managed to get most of the users from the original over to new clone by moving the cert and the server name.

I still have some imap and pop users using the old system but as soon as I get them sorted I'll get them get them to move over, if they can.  One of the problems I had was that RIM gives it's providers an interface that won't let you change your pop server even though it looks like you can.  So I'm stuck with them on the IMAP server also.

Now, as it stands I kept getting so many active sessions on the server, both IMAP and POP that it chewed up the CPU so badly that nothing ever got accomplished.  We increased the memory for the server but it still had problems.  I got a recommendation to start the server with a -u######### option which initially didn't work well.  Then it suggested a new ####### and things improved.  I seldom get more than 5 active sessions a bit over 100 idle sessions.  One other thing that may have also helped is that apparently when you assign memory to a VMWare machine half of it is a page file.  Our VM guy force it to user an extra Gig of real memory.  The combination seems to have helped.

Sorry for the sidetracking.  

Lil

>>> On 4/8/2010 at 9:27 AM, "Mary Matthews" <mlm23 at calvin.edu> wrote:

What about setting up separate GWIAs?  1 for POP and 1 for IMAP, on a different server(s) and advise your users of the change.  Been tumbling that one around in my head since BrainShare as Laura pointed out how "chatty" iPhones are.

>>> "Lilith Calbridge" <lilith at dcccd.edu> 3/10/2010 10:27 PM >>>
I'll look into these but with the state telling us their funding is going to be cut 5% each of the next two years you can imagine what that does to a lot of utility programs.  It looks like the biggest outlay of funds in the coming year is virtualization of workstations.  So, lots of funds for server farms but software???  I'll have to see how that goes.

Lil

>>> On 3/10/2010 at 9:20 PM, Rand Babcock <randbabcock at gmail.com> wrote:

How is your budget? An L4 switch can load balance pretty much any protocol. There are also software based solutions as well:

http://www.linux.com/archive/feature/46735 

http://www.inlab.de/balance.html 

http://www.cyberciti.biz/tips/load-balancer-open-source-software.html 

HTH,

Rand

On Wed, Mar 10, 2010 at 8:00 PM, Lilith Calbridge <lilith at dcccd.edu> wrote:

How is everyone handling their provisioning for POP and IMAP where you have large numbers of users? Running GWIA on NetWare I'm seeing a heavy load on the GWIA when just a few sessions are active and at some point the needle pegs at 99% and everything becomes useless. I'm about to separate the POP and IMAP from the SMTP (had to maintain it there for historical reasons) but it still looks as if it will tax the server. I've seen over 100 inactive sessions on IMAP alone with close to 30 at a time being active when it pegs out.
So how do y'all handle the load? Wouldn't it be nice if GW had a failover capability, have a farm of such servers over which the sessions could be spread?
Is there any advantage to adding a second CPU to a NetWare GWIA server?
So many questions.
Lil

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