So I basically have the same question as listed here, but no answer was ever given:
http://social.technet.microsoft.com/Forums/sqlserver/en-US/9e98829b-8391-491f-97ce-64559f27e9ca/resource-monitor-shows-disk-activity-on-wrong-disk?forum=w7itproperf
This is a Windows 2008 R2 SP1, 2 node cluster, with SQL 2008 R2 SP1. 2 instances of SQL, one running on each node. Both instances have SAN attached drives that locate the SQL data, SQL temp db, SQL Logs, SQL backups, MSDTC, etc.
One one node (one of the SQL instances), when I use Windows Resource Monitor, look at the Disk Activity, it is showing activity but on the wrong drive. It is showing the activity as taking place on
I:4\mssql10.....file name
I:6\mssql10....file name
I:7\mssql10....file name
I assume those numbers are some sort of marker or designation pointing back to the correct drive letter?
I don't see this format on any other SQL cluster we have. And the other node (other SQL instance) on this cluster shows the drive letters normally.
The files do exist but not on the I: drive. What led me to discovering this is that the sql server is having some performance slowness and in troubleshooting that issue we came across this.