[Networker] Persistent problem backing up Exchange

I am confronted with a problem backing up an Exchange 2003 serverwhere the first (and largest) of four IS storage groups consistentlyfails and the next largest storage group fails intermittently. I havea call with EMC open and I have been looking at this issue for a week.

We are pretty sure there is some sort of network issue at work here,but our network administrator is at a loss as to what it could be.

This Exchange server consists of two Microsoft cluster nodes (Windows2003) and this server has been in production since July. IS backupshave been intermittently failing, but since about ten days ago, thelargest storage group won't back up at all, except once when I triedit last week.

There is nothing too illuminating in the event logs or on the logsin /nsr/applogs either, except for a consistently occurring networkerror. When the backup starts, it quickly gets to a very fastthroughput and I have tried doing backups at a variety of differenttimes. The largest storage group is probably pretty small compared tosome Exchange shops. Its around 80GB and there are only around 200users on this server.

I tried putting in an NSR_KEEPALIVE_WAIT environment variable with avalue of 30 on both cluster nodes. I also tried putting in akeepalilvewait TCP/IP variable in the registry on both nodes. Neithermade a difference.

The event logs show backup failures, but nothing before or after thefailed events is consistent. We do run Symanteck's Anti-virussoftware on this server, but we tried disabling and running a backup,but that backup also failed so we enabled the a-v software again.

I am a Unix and Mac guy, so Windows 2003 is not my strong suit andthe Exchange administrator here is inexperienced with it. We arelearning by the seat of our pants about this server. This cluster andExchange server was set up by Microsoft Professional Services and Iset up the backups with assistance from EMC's tech support.

The hardware consists of a pair of Dell blades and GB ethernet. TheDell ethernet card driver does not have any options to change howflow control is set, and EMC suggested we try using full flow controlon it. This is the latest driver that Dell offers and I am not evensure that's our path to success.

If anyone has any ideas on anything I might have overlooked on how Ican solve this problem, please let me know.


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