Backup Exec job rate query
We are using Backup Exec 12.5 to backup our servers to a pair of NAS devices (and these are later duplicated to tape). Both of these NAS boxes have 1Gbit network connections (and this is set in the card config to avoid it dropping to 100Mbit or lower), and plenty of disk space (6TB and 8TB). They are connected to the network via a dedicated gigabit switch and fibre, both of which (as far as possible) carry only traffic for backups. Both NAS devices are available to Backup Exec as a device pool, with no differentiation - jobs are targeted at the pool.
Originally, the problem appeared to be as follows: jobs backing up to the first NAS ran at 400+MB/min (some around 600+MB/min). Jobs backing up to the second NAS ran at around 30-50MB/min. Initially, this appeared to be a loading issue - but reducing the number of simultaneous jobs didn't really make a difference. I now also see the issue when jobs are running to either NAS, apparently regardless of loading.
I am at a bit of a loss as to what to try changing - I've rebooted all devices in the chain to no effect; it doesn't appear to be caused by certain jobs or certain servers, so if anyone has any suggestions, I'd be most grateful!