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Exchange 5.5 MTA Major problem

MCPJoe asked
Medium Priority
Last Modified: 2008-01-09
I have 4 Exchange 5.5 servers, one main server that has the IMS installed.  Suddenly today the MTA on the main Exchange 5.5 server started failing.  The MTA service would stop.  I noticed its creating hundreds of .dat files of varying size, but when opening with notepad, they just have a solid black block at the top left corner.  They don't appear to be valid files.  This is our main server, incoming and outgoing mail is routed through this one server.  Its important I get it back online ASAP.  I've run the MTACHECK tool and it finds nothing wrong.  The MTA service will run but the MTADATA folder has over 10,000 files in it over 3GB of data.  Every time I start the MTA service, it creates hundreds of files per minute and is going nuts.  I'm down to 300MB of freespace on this machine.  Any ideas or suggestions?

This is a mixed org with Exchange 2003 and the ADC as well.  I've already checked internet connectivity and DNS confg.  Everything seems to be working fine, except for the MTA service.

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Update: After a few reboots, disabling and re-enabling my AV software, and doing any little troubleshooting here and there I could think of; Exchange 5.5 is finally processing mail in the MTADATA Folder.  At last reboot I had 100MB of free disk space due to this issue.  I am now at almost 1GB of freespace, so I'm about 1/3 of the way back to normal.  The MTA seems to be processing mail now but slowly.  I'm afriad that when I re-enable mail flow from external incoming messages back to this server, we will run into the same issue again.  Seems that the issue was really only for internal mail, as I just sent a test from telnet through the failing server and received it very quickly at my mailbox on an Exchange 2003 server.  So the thousands of messages queued in the MTADATA folder are for internal mail?  How can that be?  Outgoing and incoming over SMTP seem to be ok, just need to make sure the MTA folder doesn't consume more disk space than it has available.  Its currently only on a 9GB partition, which should be enough, does anyone have any idea what would cause the MTA to generate so much internal activity?

I am going to recommend at this point, that we move remaining mailboxes on this box to one of the other Exchange 5.5 boxes, move public folders, etc, to another box as well.  We could also install a new IMC on one of the other Exchange 5.5 boxes and route all outgoing mail to one of the Exchange 2003 machines or directly to the internet.  We are urgently trying to migrate away from Exchange 5.5 as quickly as we can.  

Any tips on this process.  Especially for the following:

1. Remove IMC on failing Exchange 5.5 server
2. Install new IMC on either a different Exchange 5.5 machine or on one of the Exchange 2003 machines

DISCLAIMER From the Moderators: the links in this thread require a paid registration to view.

I would suggest starting with reapplying SP4 for Exchange 5.5. There is a chance that this will fix your problem.
Here are examples (screencasts) of moving/restoring exchange 5.5 services to a different machine:





UPDATE: The problem was not with the MTA itself, but rather a disk space issue.  Just before I experienced this problem, I had enabled a replica of one of the public folders on the server in question, to replicate to another server, running Exchange 2003.  Since Exchange 5.5 uses the X.400 connector over the MTA to transfer messages, even public folder replication, Exchange 5.5 had dumped thousands of files into the MTADATA folder.  Rather than stream the information real time to the new replica server, Exchange 5.5 dumped copies of each message into the MTA for transfer to Exchange 2003.  Since I only have 2GB or so of free space on this partition, and was transferring over 4GB of public folder data, needless to say this caused an issue.  Fortunately, at one point, we reached a critical point, Exchange 5.5 had sent enough public folder data so it would now leave 100MB free on the partition the MTA is on.  From there on, the free space started to increase, as Exchange 5.5 delivered the public folder data to exchange 2003.  The problem worked itself out and both systems are working normally.  I now know not to replicate public folders larger than a few GB from this server to another server without keeping a close eye on the MTA partition free space.  Whew!!!
PAQed with points refunded (500)

EE Admin

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