Recover Unowned LUN

Can you put a snap of the LUN properties here ? If 'the array is operating normally' , only hotspare disks should be unowned I think.

It is not possible to include a screen shot at this time (I'll try to get one on later), but here is a fragment of the NaviCLI getlun output.

The LUN is right in there with the Hot Spares.

I also notice I get a '0x951 CRU Signature error' for each drive on the DAE during SP startup...

Name                        LUN 2
Minimum latency reads N/A

RAID Type:                  RAID6
RAIDGroup ID:               1
State:                      Bound
Stripe Crossing:            0
Element Size:               128
Current owner:              Unknown
Offset:                     0
Auto-trespass:              DISABLED
Auto-assign:                DISABLED
Write cache:                ENABLED
Read cache:                 ENABLED
Idle Threshold:             0
Idle Delay Time:            20
Write Aside Size:           2048
Default Owner:              SP B
Rebuild Priority:           High
Verify Priority:            Medium
Prct Reads Forced Flushed:  0
Prct Writes Forced Flushed: 0
Prct Rebuilt:               100
Prct Bound:                 100
LUN Capacity(Megabytes):    5634820
LUN Capacity(Blocks):       11540112384

Is there any data in the LUN ?

Disks in the RAID Group 1 span across the DAE and DPE  (RG 1 is made of disks from both the enclosures) ?

Hmm. I guess from the absence of any further response to this that it will not be possible to recover any data.

I will have to move into the recycle phase. Pity. Thanks for your response so far.

Mark, if it is critical data your best bet would be to contact EMC (or Dell in this case). I think we're all at a loss on how to proceed here.. I sure am

Usually you can get a LUN online again by rightclicking it and selecting "Bring Online" or anything. If that doesn't work, it's "dumpster diving in the event log"-time...

I'm also unsure what happens when you attach a DAE full of drives to another DPE. If you remove and reinsert a single drive in a DAE, it's empty for sure. But for a complete DAE to be attached to a different storage system... I'm not sure...

Best of luck!

Thanks Jon. I tried 'Bring Online' with no luck so I guess the cause is lost, but now we do know what happens when you attach a DAE full of drives to another DPE - .

The other DPE had a DAE with the same identity. The disks on that DAE were all unconfigured - and now the disks on this DAE are all as good as unconfigured.

Thanks all for your input.

Mark

If you haven’t tried it yet, power down the entire array, ensure all DPE/DAE loop connections are correct, power on the DAE’s first and ensure their enclosure ID’s are correct, then power up the array. If the LUN went unowned as a result of a loop issue or enclosure ID conflict, it could bring it back.

If, however, the other array wrote data on the disks (unlikely from just adding the DAE to loop temporarily) it may not be possible to bring it back online without EMC Support. EMC Engineering can go in and recover metadata that customers cannot see deep in the array subsystem.

Anyway, give the power cycle a shot.

Richard J Anderson

I would second Richard's recommendation. Apologies for the delay though!

Anyhow,

Step 1: Make sure all the cabling and DAE ID (Bust with Encl ID) is correct. (Correct Order and symmetry)

Re-arrange to the Original Setup for the Bus, Encl, if the order is incorrect.

Step 2: Follow Power down procedure for the Stroage Array.

Step 3: Once, the array is power up completely wait for 10-15 mins till all the services of the storage array is started/online.

Verify the Status of the RAID Group/Storage Pool and LUN Ownership.

If it still shows unowned try to Bring Online or trespass the LUN.

If still the same, as Richard and Jon mentioned, there is nothing much a customer can do for recovery. EMC Engineering might need to intervene and comment on what can be done next.

Thanks Richard and Ankit. Unfortunately, even after power-cycling the entire array and double-checking the cabling, the LUN was still Unowned and I could not Bring it Online. I will now re-use the array for another project.

Thanks once again for all your suggestions.

Mark