CPU usage is ideal... as is everything else. It will start copying a file, say 700MB, then about 100MB in it will hang, and stop copying. It hangs for everyone else trying to access files on the server too.
After about a minute it will come back to live and start copying the file again.
Image of when it hangs: https://img.skitch.com/20120417-fwyju56xegtj78yc7je6nf7eqk.png
I have had a look at the HDD, and it seems to be quite fragmented. I was defragmenting it over the weekend, but it only got about 15% in, so had to cancel it. https://img.skitch.com/20120417-pbuuxgc5tmg7bxassprbuq29id.png
This partition is running on a RAID 1 HDD.
We (about 20) are all connected with gigabit ethernet. But at the time of this test I was the only one copying a large file.
It's been driving me nuts.
About a month ago I swapped both HDDs with slightly bigger ones.
Both "Write caching" and "Advanced performance" are disabled with the 2 new HDDs. I think this may have been enabled before.
I recall reading somewhere that these settings could cause issues when enabled with our tape backups.
Does this really make a difference?