Yep, we've seen that the 100% CPU case too. In our case, we whacked an extra couple of 
CPUs in the server (bringing it up to 4) which helped a *lot*. We still get CPU 
spikes, but they're much less severe, and if they do hit 100% they come down on their 
own after 30 secs or 1 minute or so. I tested the big mailbox theory, but couldn't 
really find any correlation. I suspect Ipswitch are currently using the indexes 
properly in the latest webmail code, so size of mailbox is (fairly) irrelevant. Things 
that might be worth investigating here, though...
 
- Does 50MB of large numbers of small messages behave slower (or quicker) than 50MB of 
small numbers of large messages
- What happens if the index file is removed and IMail has to rebuild it?
 
The profile of a CPU spike is very interesting. You sometimes get a stepped effect... 
where the load on the CPU goes up in very definite steps (i.e. 25%, then 50%, then 
75%, then 100%, then 75%...). No idea what causes that, but since we're on a 4 CPU 
box, it may be an individual thread is getting tied up. My best guess is some kind of 
locking effect (possibly caused by an incoming message on a mailbox we're trying to 
read), where accessing a locked object is badly handled, but I have no evidence. 
 
Would be very interested in anything anyone discovers!
 
Cheers,
 
Clive Williams
 
-----Original Message----- 
From: Tom G [mailto:[EMAIL PROTECTED] 
Sent: Thu 01-Apr-04 10:03 PM 
To: [EMAIL PROTECTED] 
Cc: 
Subject: RE: [IMail Forum] iwebmsg.exe 100% CPU



        Eric
        
        I'm an ISP and have many email servers.  I have to limit my users to
        10MB email boxes.  Iwebmess still hammers the servers but not as bad if
        the mailboxes are kept to a minimum. 
        
        To test, set up a new imail server, copy over a 50MB + main.mbx, then
        access that account using the web based interface.  Watch task manager,
        it will skyrocket.
        
        My theory is that if you create a new interface, it will still be a very
        expensive process to access those big mailboxes.  The problem is that
        iwebmess hammers the CPU to 100%.  If you designed something that would
        make use of the CPU, but not hammer it to death, you might have
        something.
        
        Tom
        
        -----Original Message-----
        From: [EMAIL PROTECTED]
        [mailto:[EMAIL PROTECTED] On Behalf Of Eric Coffman
        Sent: Tuesday, March 30, 2004 3:36 PM
        To: [EMAIL PROTECTED]
        Subject: [IMail Forum] iwebmsg.exe 100% CPU
        
        
        Another reason for my topic about having an ASP/IIS version of Web
        messaging... My server has 2 times in the past 24 hours had Iwebmsg.exe
        consume 100% cpu until I restarted the service. I am on the latest
        version of Imail and have about 100 times the hardware necessary for my
        load. 2000 messages a day on a dual 933 with 2 gig of ram.
        
        Anyone have any idea why iwebmsg.exe randomly uses 100% cpu? Anything I
        can do to make it stop doing this?
        
        Eric
        
        
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