FireWire RAID breaking

[lundp]

I have a PowerMac G4 Dual Processor with 1GHz processors running as a file server. The data is stored on the a pair of LaCie 250 GB drives arranged in a mirror RAID array. The array has functioned fine for a year. Recently we began to implement backups with Retrospect 6.1, using a couple other 250 GB hard drives (also FireWire).

The initial backup seems to go fine. But when the script runs for the next backup, the backup gets very slow and virtually stops. Force quiting Retrospect takes some doing, but will cancel the backup. However, I found that the RAID was broken and that Mac OS X wanted to rebuild the RAID. That is fine, but now whenever I copy files to the backup drives, the process get slower and grinds to a halt after a while. File access to the server gets very slow too.

I received two new FireWire hard drives and built another RAID for the server and moved all the data over to that RAID. Retrospect seems to have done the same thing again. Slow performance and virtual stops in backups and file copies.

Can the internal FireWire interface of the PowerMac G4 be at fault? I am not sure why the hardware device reports failure and one RAID drive goes off line. I am sure the hard drives are fine. The Mac OS X software is on its own SCSI hard drive in the server and is fine.

Thanks for any insights.