How to cleanly remove MSA2040 disks

[Luca]

We are in the process of switching to SSD disks in our MSA2040 and I haven't found any documentation on how to spin down and extract the SAS disks safely without logging a hot unplug event. I have removed mappings and volumes and deleted the disk group and the disks are now shown as AVAIL as expected. At this point as we still have a LUN in production on the same chassis I would like to avoid shutting the whole thing down to extract the unused disks. So I'd like to know if there is a spin-down command or similar to then safely remove the offlined disks. Also, when the disks are tagged as AVAILABLE what would happen if they were inserted in another MSA? Would they appear as foreign or LEFTOVR? I don't think so as they have been properly deallocated so they shouldn't retain any metadata but I'd like to be sure as we would be giving them to a partner as used. Thanks for any feedback!

[support_s]

System recommended content:

1. HP-UX 11.x - How to Remove Disconnected (NO_HW or disabled) Disks from Ioscan and Vxdisk List

2. How to remove TMF dumps from disk

Please click on "Thumbs Up/Kudo" icon to give a "Kudo".

Thank you for being a HPE valuable community member.

[Luca]

Hi @support_s, thanks for the links but I am unable to access the hp ux resources.

[PrathibaC]

Hello Luca,

You may refer the following links:

1. MSA 2040 User Guide .
2. HPE MSA 1040, 2040, 2042 SAN Storage - End Of Life Announcement .

[Luca]

Hi PrathibaC,

  thanks - I have these guides (SMU Ref Manual and CLI Manual) - the problem is I have found NO WHERE any reference to how to safely HOT UNPLUG a disk. Usually, in other SANs you can issue a DOWN DISK command which spins the disk down so you can safely remove it from the slot without having it log a hot unplug event. The disk of course must be free and unallocated.

I would like to know specifically if it is possible to safely unplug an unallocated (AVAIL) disk in the MSA, without it logging a hot unplug count. This is because these disks have to be repurposed in another MSA. There is also a specific repurpose CLI command which the MSA supports, namely the "set disk [id] repurpose" command which securely wipes all data on encryption supporting disks. However this only allows the disk to be repurposed on a different MSA, it has no reference to the hot unplug / spin down possibility.

Does anyone know if a disk in the AVAIL state can be safely unplugged from a working/production MSA?

Alternatively, the only way to do this properly would be to shutdown both controllers, power down the chassis and remove the disks.

Thanks

[Shawn_K]

@Luca 

The MSA does not have a spin-down command. To safely remove a drive you need to ensure there is no disk-group, pool, or Vdisk associated with the drive. If as you say it is marked in an AVAIL state it would indicate you have already removed any association with the above. 

If the drive is marked as AVAIL you can safely unplug and remove it from the bay it currently is in. You will get a informational event logged for a SAS PHY being removed and a rescan of all SAS PHYs but this is as per design. Be careful you remove the correct drive as you indicate you still have a production LUN on the system.

As long as you are removing the correct drive, there will be no disruption to your production LUN. You can then hot plug the drive into your other MSA array. As long as all the vdisk, disk-group, LUN information was correctly removed from the first array, the drive will be discovered through a SAS PHY rescan event and marked as AVAIL in the second MSA array. 

I work for Hewlett Packard Enterprise. The comments in this post are my own and do not represent an official reply from HPE. No warranty or guarantees of any kind are expressed in my reply.

Cheers,
Shawn

[Luca]

Hi Shawn, thanks for your feedback. What you say is in fact as I suspected. The only question lurking in my mind is: do you know if when we hot unplug any "AVAIL" disk there will be a hot unplug event logged in the SMART status of the disk and in any case would this operation have any history when the disk is repurposed? From my experience from prior storages (P2000) once the disk is not part of any volume and is "unallocated" there should be no METADATA left on the disk itself being transported and read from a new enclosure when re-inserted and should behave as a "clean" or new disk in all senses (apart from the logged hours).

Thanks for your insight!

[Shawn_K · Accepted solution]

@Luca 

Even in newer versions of the MSA array, when a new disk is inserted, as long as there is no metadata on the disk, the new system will see the drive as AVAIL/NEW. You will not see the previous unplug/remove event on the new system.

You should be aware that repurposing drives can have some risk due to the logged hours of operation. Moving a drive does not refresh those logged hours and the drive may fail sooner than expected for the second MSA system if they are expecting a "new" drive.

I work for Hewlett Packard Enterprise. The comments in this post are my own and do not represent an official reply from HPE. No warranty or guarantees of any kind are expressed in my reply.

Cheers,
Shawn

[Luca]

Yes, I am aware of the "aging" of the used disks and thus higher risk of failure and that's why they will be used in a less critical backup/replica scenario (which is why we opted to switch to SSDs and change their role and breath some more life into this 2040). Thanks for the feed back and confirmation - I will proceed to hot unplug them one by one, taking care to check the status of the MSA.

Cheers!