perhaps this article has something to do with it, though this is just during upgrade. KB#85130
Issue:
During upgrade from GeoSynchrony 4.2 to 5.0 (although this can happen during any upgrade), connectivity loss to VPLEX volumes occurs during first upgrade actions.
Cause:
ESXi servers, hosting Microsoft Windows Cluster 2008 nodes, due to their use of RDMP and NMP devices, did not, and could not, handle the loss of their paths (and loss of SCSI-3 reservations) during the upgrade.
This is due to how both MSCS 2008 and ESXi handle the initial disk reservations when the cluster starts up. Using ESXi's NMP, the cluster only sees one path on which to place the SCSI-3 (PER) reservations, thus locking those disks to that cluster, down that single/primary path. When that path failed during the VPLEX NDU, ESXi did fail the I/O over to the secondary path on the server, but MSCS was unable to establish new reservations to the disks down the second path, due to VPLEX locking out any reservation modifications during the upgrade operation on the VPLEX directors. This inability to put new reservations on the clustered disks, caused the MSCS cluster nodes to panic and brought down the entire cluster.
Resolution:
Final result of the analysis has shown that the optimal solution is to install current version of PowerPath/VE on the ESXi servers that host MSCS cluster nodes. This permits the SCSI-3 disk reservations to be applied down all active paths to storage. This will prevent any issues during future NDU events.
jroczniak
1 Rookie
•
30 Posts
0
February 5th, 2015 07:00
Ever find a definitive answer to this? I have some unusual scsi reservation activity causing path downs on vsphere after upgrading from 5.0 to 5.3
Only trying to add new vplex storage to the metrocluster and had major problems.
Thanks!
ray1119
14 Posts
0
April 23rd, 2015 02:00
perhaps this article has something to do with it, though this is just during upgrade. KB#85130
Issue:
During upgrade from GeoSynchrony 4.2 to 5.0 (although this can happen during any upgrade), connectivity loss to VPLEX volumes occurs during first upgrade actions.
Cause:
ESXi servers, hosting Microsoft Windows Cluster 2008 nodes, due to their use of RDMP and NMP devices, did not, and could not, handle the loss of their paths (and loss of SCSI-3 reservations) during the upgrade.
This is due to how both MSCS 2008 and ESXi handle the initial disk reservations when the cluster starts up. Using ESXi's NMP, the cluster only sees one path on which to place the SCSI-3 (PER) reservations, thus locking those disks to that cluster, down that single/primary path. When that path failed during the VPLEX NDU, ESXi did fail the I/O over to the secondary path on the server, but MSCS was unable to establish new reservations to the disks down the second path, due to VPLEX locking out any reservation modifications during the upgrade operation on the VPLEX directors. This inability to put new reservations on the clustered disks, caused the MSCS cluster nodes to panic and brought down the entire cluster.
Resolution:
Final result of the analysis has shown that the optimal solution is to install current version of PowerPath/VE on the ESXi servers that host MSCS cluster nodes. This permits the SCSI-3 disk reservations to be applied down all active paths to storage. This will prevent any issues during future NDU events.