I am planning to my SQL server databases (plus TLogs and TempDB) to a new LUN on our iSCSI SAN. The current LUN's used by these of these files are on their own two disk RAID 1 disk group and I'm going to a larger but shared 14 disk RAID 10 disk group. I want to measure the performance of the current configuration and the new configuration as I move each database over and ensure that I am not starting to hit any disk performance issues (or see if I am actually increasing the performance).
There are a bunch of posts on the internet on SQL performance counters such as this one, but I am really interested in just the few that are related to network/disk usage and any latency or limits that associated with disk reads/writes. What are some of the important SQL or Windows performance counters that I should look at to create a current baseline/comparison for iSCSI disk access for SQL?