FileMaker stalls out on network - NT Server?

[HazMatt]

Running FileMaker Server 5 on Windows NT. Here's a typical performance monitor screenshot.

My problem is every once in a while (probably once or twice a day) I get the little double-arrow cursor with the squiggly line. FileMaker basically freezes up for a minute or two, then finally resumes where it left off. Most often this seems to happen when switching layouts, and I can see half the elements on the layout have been drawn (based on the front / back level). The rest of the layout just shows blank, until it kicks in again.

This has happened to at least one other OS 9 machine, so I don't think it's just me...

[Vaughan]

This occurs when FMS is flushing its cache or backing up the database.

[HazMatt]

Well, I get the coffee cup icon when it's running a backup, so it must be the flushing the cache. How can I tell when it's doing this on the NT Server? The performance monitor doesn't appear to change too much when this happens...