To check what multipathing settings a Windows server is using you can use the command line utility mpclaim.
To check the policy your volumes are currently using:
mpclaim -s -d MPIO Disk System Disk LB Policy DSM Name ----------------------------------------------------- MPIO Disk1 Disk 2 RR Microsoft DSM MPIO Disk0 Disk 1 RR Microsoft DSM
The multipathing load balancing policy is shown under LB policy so in the above case RR for Round Robin.
To view the number of paths there are to a volume enter the command mpclaim -s -d followed by the system disk number you want more details on. For example:
mpclaim -s -d 1 MPIO Disk1: 08 Paths, Round Robin, Symmetric Access Controlling DSM: Microsoft DSM SN: 6002AE000000013B006E3B Supported Load Balance Policies: FOO RR RRWS LQD WP LB Path ID State SCSI Address Weight ---------------------------------------------------------- 0000000087060003 Active/Optimized 005|000|003|001 0 * TPG_State : Active/Optimized , TPG_Id: 256, : 124 0000000087060002 Active/Optimized 005|000|002|001 0 * TPG_State : Active/Optimized , TPG_Id: 256, : 122 0000000087060001 Active/Optimized 005|000|001|001 0 * TPG_State : Active/Optimized , TPG_Id: 256, : 24 0000000087060000 Active/Optimized 005|000|000|001 0 * TPG_State : Active/Optimized , TPG_Id: 256, : 22 0000000087060003 Active/Optimized 004|000|003|001 0 * TPG_State : Active/Optimized , TPG_Id: 256, : 123 0000000087060002 Active/Optimized 004|000|002|001 0 * TPG_State : Active/Optimized , TPG_Id: 256, : 121 0000000087060001 Active/Optimized 004|000|001|001 0 * TPG_State : Active/Optimized , TPG_Id: 256, : 23 0000000087060000 Active/Optimized 004|000|000|001 0 * TPG_State : Active/Optimized , TPG_Id: 256, : 21
Thank you. Been looking high and low for a quick option to verify multipath is working for a disk.
Glad you found it useful and thanks for taking the time to respond.
This is an insanely stupidly complicated process. This is windows – whatever happened to the “simple point-and-click solution?”
Is there a way to find the disk details at once for all the drives/disks? i am having 3Par in windows 2008.
From Windows 2008 you can use storage explorer and look inside storage manager. Those disk that device ID 3PARDADVV belong to 3PAR
Thanks! That was really helpful.
Thanks that was a really simple helpful tutorial.