Recovering the storage systems: primary site failure with external storage system

Global Active Device for VSP One Block
Version
10.5.x
Audience
anonymous
Part Number
MK-23VSP1B011-10
ft:lastEdition
2026-05-04

If a failure occurs at the primary site in a configuration with the external storage system for the quorum disk located at the primary site, the failure might affect the primary storage system and the external storage system simultaneously. In this case, the GAD pair is suspended, and access to the GAD volumes stops.

Failure at the primary site (external storage system at the primary site)



Failure locations

Reference codes of SIMs that might be issued

Can the volume access to the GAD volumes?1

Primary storage system

Secondary storage system

P-VOL

S-VOL

Both the primary storage system and the external storage system for the quorum disk

Depends on the failure type2

DD0xyy

DD2xyy

DD3xyy

2180xx

21D0xx

21D2xx

EF5xyy

EFD000

FF5xyy

DEF0zz

No

No3

Notes:

  1. Hardware such as drives, cache, channel board (CHB), disk board (DKB), and MPU is redundant in the storage system configuration. Even if a failure occurs in a part of redundant hardware, the failure does not cause a GAD pair being suspended, or an inaccessible GAD volume. The failure does not cause the GAD pair suspended, or the inaccessible GAD volume even if a failure occurs in a part of hardware, if the following physical paths are redundant.
    • Between a server and a storage systems of the primary and secondary sites
    • Between an external storage system and storage systems of the primary and secondary sites
    • Between storage systems of the primary and secondary sites
  2. A SIM that corresponds to the failure type is issued. You might not be able to view SIMs according to the failure type.
  3. You can access the S-VOL, if the pair status of the S-VOL is SSWS, even if a failure occurs.

You can reduce the time to recover from suspended GAD pair operations by forcibly changing the I/O mode because you will not need to re-create GAD pairs and you can recover by resynchronization. See Forcibly changing the I/O mode of GAD pairs for recovery.

  1. Using the multi-path software, delete the path to the GAD P-VOL.
  2. At the secondary storage system, delete the GAD pair forcibly.

    When deleting the pair forcibly, do not delete the virtual ID, which allows the volume to be accessed from the server. 

    pairsplit -g oraHA -d dev1 -RFV -IH2
  3. Confirm that the virtual LDEV ID is not deleted. 
    raidcom get ldev -ldev_id 0x2222 -fx -IH2
(Omitted)
LDEV : 2222
VIR_LDEV : 1111
(Omitted)
  4. Confirm that the GAD pair is deleted.
  5. Using the multi-path software, resume I/Os from the server to the GAD S-VOL.
  6. Restore the primary storage system from the failure.
  7. At the primary storage system, delete the GAD pair forcibly.

    When deleting the pair forcibly, delete the LDEV ID so that the volume cannot be accessed from the server.

    Depending on the failure type of the primary storage system, after the primary storage system is restored from a failure, the pair status of the P-VOL might change to SMPL, and the GAD reserve attribute might be set. In this case, you do not need to delete the GAD pair forcibly. 

    pairsplit -g oraHA -d dev1 -SF -IH1
  8. Confirm that the virtual LDEV ID indicates GAD reserve. 
    raidcom get ldev -ldev_id 0x1111 -fx -IH1
(Omitted)
LDEV : 1111
VIR_LDEV : ffff
(Omitted)

    VIR_LDEV : ffff indicates GAD reserve.

  9. Confirm that the GAD pair is deleted.
  10. Restore the external storage system from a failure.
  11. From the primary and secondary storage systems, delete the quorum disk.

    Depending on the failure type of the external storage system, after the external storage system is restored from a failure, a quorum disk can be deleted. In this case, you do not need to delete the quorum disk.

  12. From the primary and secondary storage systems, add a quorum disk.
  13. From the secondary storage system, re-create a GAD pair.
    If a failure occurs after the one volume capacity of a GAD pair can be expanded, the creation, resync, swap resync, and horctakeover operations of the GAD pair cannot be performed because the capacity of both the volumes is not the same. Make sure to expand the other volume capacity so that the capacity of both the volumes is the same, and then retry the operation.
    If you accidentally delete the virtual LDEV ID of the S-VOL, you cannot create a GAD pair again. See Setting correct virtual LDEV ID values and set the correct value for the virtual LDEV ID.

    The default virtual LDEV ID is the same as the actual LDEV ID. After setting the virtual LDEV ID again, verify that the virtual LDEV ID is the same as the actual LDEV ID of the P-VOL using the confirmation command.

  14. Using the multi-path software, add a path to the GAD P-VOL, and then resume I/Os.
  15. Reverse the P-VOL and the S-VOL if necessary.
    If a failure occurs after the one volume capacity of a GAD pair can be expanded, the creation, resync, swap resync, and horctakeover operations of the GAD pair cannot be performed because the capacity of both the volumes is not the same. Make sure to expand the other volume capacity so that the capacity of both the volumes is the same, and then retry the operation.