Intermittent VERY slow backups

[sdawson]

Running Pro V7.5.287, latest RDU, on WinXP Pro, backing up to a LaCie AIT drive via firewire. I've started getting an intermittent problem where part of a backup will run extremely slowly. Here's an example from last night's recycle backup:

 

- 21/05/2007 12:23:34 AM: Copying Data (D:)

21/05/2007 5:45:36 AM: Snapshot stored, 3,024 KB

21/05/2007 5:45:44 AM: Comparing Data (D:)

21/05/2007 6:10:32 AM: Execution completed successfully

Completed: 8669 files, 5.0 GB

Performance: 29.2 MB/minute (15.7 copy, 208.2 compare)

Duration: 05:46:58 (00:01:08 idle/loading/preparing)

 

In this case, it took 5 hours to do a relatively small backup. All the other drives in this same backup were backed up at normal speed. The problem only started happening fairly recently, and isn't always just this D drive. From what I've seen when I'm around when the problem happens, everything just seems to have its finger in its ear (ie doing nothing) for long periods. No tape activity, no nothing. Any ideas where I start to diagnose this problem? Thanks.