topic Re: Physical vDisk Move in MSA Storage

Physical vDisk Move

Klunk — Thu, 17 Apr 2014 09:40:14 GMT

Does anybody know if it is possible to shut down an MSA2000 G2, eject the physical disks in a vDisk and then insert these disks into an MSA2000 G3 (P2000) and power it up and in so doing, retain the vDisk (and the volumes it contains).

I can think of no reason why this would not work, but has anybody actually done it please? I want to migrate a volume to new hardware and this seems like the simplest solution (I will be backing it up first). Both MSAs are at latest firmware and the disks are supported in both systems.

Re: Physical vDisk Move

Torsten. — Thu, 17 Apr 2014 10:17:28 GMT

The question is if this works if there are other vdisks in the arrays.

I know for sure if you replace both controllers (basically the same procedure) it works, the system get all relevant information from the disks, except IP addresses and WWID/WWN of the array.

Re: Physical vDisk Move

Klunk — Thu, 17 Apr 2014 10:21:40 GMT

Hi Torsten,

Thankyou for your reply. There are pre-existing vDisks on the P2000 that I wish to retain.

Re: Physical vDisk Move

Torsten. — Thu, 17 Apr 2014 10:25:28 GMT

I don't think the system is able to "merge" the information from 2 different systems. I guess it will take the moved disks as new disks.

Re: Physical vDisk Move

Klunk — Thu, 17 Apr 2014 10:31:23 GMT

As a rule, the RAID data is held on the disks and additional settings such as LUN masks etc are held in the controller. So my guess would be different and that it would adopt (or merge) the new array (vDisk). But it is only a guess and I do not want to risk my P2000 vDisks :-(

Re: Physical vDisk Move

Torsten. — Thu, 17 Apr 2014 12:01:43 GMT

>> As a rule, the RAID data is held on the disks and additional settings such as LUN masks etc are held in the controller.

No. Everything is held on the disks (except IP address etc on the enclosure backplane), not exactly sure what is held on the controllers.

(think of single controller arrays, a failed controller would be a real desaster)

In the past I converted some MSA2000 from SAS to fibre or Iscsi and even swapped out 2 bad controllers at the same time, always with all data in place. In all such cases the array will be powered off, both controllers removed, 2 new controllers inserted and powered on.

Re: Physical vDisk Move

Klunk — Thu, 17 Apr 2014 10:47:55 GMT

Sorry, but if what you say were true, Hosts would not need to be remapped after an MSA2000 G2 to P2000 controller upgrade. But P2000 the upgrade guide quite clearly states that hosts do need to be remapped:

Upgrade procedure

The upgrade procedure for the MSA2000 G2 includes the following steps:

 Shut down each controller
 Remove and replace the controllers
 Re-enter system settings
 Assign or rename port WWN to assigned nicknames
 Assign or rename port IQN host nicknames, if applicable
 Re-enter Explicit Volume Mappings
 Re-enter user information
 Re-enter services information
 Verify Fibre Channel switch configuration
 [P2000 G3 FC/iSCSI MSA, P2000 G3 10 GbE iSCSI MSA, and P2000 G3 iSCSI MSA] Re-establish iSCSI connectivity, if necessary
 Complete the upgrade

So clearly some data is in the controllers, that being said, if you do not use explicit mappings (I always do), perhaps that explains your reported ability to do in-situ upgrade.

Anyway, it doesnt make my dilema any clearer sadly.

All the best.

Re: Physical vDisk Move

Torsten. — Thu, 17 Apr 2014 12:54:38 GMT

I'm not sure if the metadata is stored on all disks of a vdisk or even on all disks (not per vdisk). I assume it is stored per vdisk, but I'm not sure.

The reference guide also says "Volume mapping settings are stored in disk-drive metadata.".

Of course you need to redo the mappings if the topology is changing.

In a worst case you would see a lot of your disks in a leftover status after moving your disks to another array with existing disks - they did not match the configuration, data lost on that drives.