The issue is rarely bandwidth over the 1GB link, the issues usually occur because the storage target is not configured properly for the applications using it.
From searchstorage.com SAN All-in-One Guide SAN:Chapter 2 page 11[/b].
http://viewer.bitpipe.com/viewer/viewDocument.do?accessId=5758465
Bandwidth has an impact on performance when large requests are being processed.
In this case, most of the work is spent transferring the data over the network making bandwidth the critical
path. However, for smaller read and write requests the storage system spends more time accessing data making
the CPU, cache memory, bus speeds and hard drives more important to overall application performance.
Unless you have a bandwidth intensive application (e.g., streaming media or backup data) the difference in
performance will be minimal. Enterprise Strategy Group (ESG) Lab has tested storage systems that support
iSCSI and FC and the performance difference is minimal — ranging between five- and 15%.
In fact, an iSCSI storage system can actually outperform a FC-based product depending on other, more
important factors than bandwidth — including the number of processors, host ports, cache memory and
disk drives and how wide they can be striped.
The slowest component of the storage performance chain is the hard disk drives.
So if you have any applications like mentioned above you may want to be sure they use a seperate link if available.
