Hello starragheckert,

There are few things you can do to increase performance:
* Use a 10G NICs ( If you keep using the 1G NICS is your bottle neck)
* Use SAS drives. As SAS drives shows better performance than SATA (you can Google this, a good web to check is tomshardware.com)
* Make sure to upgrade to latest version of your DSS (1.21 is old) I have 1.37. BUT be aware to backup your data. As starting from 1.28 or 1.30 (Iam not sure you can ask open-e guys) open-e start using Block-IO instead of File-IO. So backup, upgrade then restore them back.

mmm.. That what I can think about (Connection, drive speed and system upgrade)

Let me hear back from you.. its always good to hear success stories