Pair condition and recovery: external storage system failure

Global Active Device for VSP One Block
Version
10.5.x
File Size
25537 KB
Audience
anonymous
Part Number
MK-23VSP1B011-11
ft:lastEdition
2026-06-23

The following table shows transitions for pair status and I/O mode, the volumes that are accessible from the server, and the location of the latest data when you can no longer use the external storage system.

Before failure

After failure

Pair status and I/O mode

Pair status and I/O mode

Volume accessible from the server

Volume with latest data

P-VOL

S-VOL

P-VOL

S-VOL

P-VOL

S-VOL

PAIR (Mirror(RL))1

PAIR (Mirror(RL))1

PAIR (Mirror(RL))

PAIR (Block)

OK

NG

Both P-VOL and S-VOL

PAIR (Mirror(RL))

PAIR (Mirror(RL))

PAIR (Mirror(RL))

PAIR (Mirror(RL))

OK

OK

Both P-VOL and S-VOL

PAIR (Mirror(RL))

PAIR (Block)

PAIR (Mirror(RL))

PAIR (Block)

OK

NG

Both P-VOL and S-VOL

COPY (Mirror(RL))

COPY (Block)

COPY (Mirror(RL))2

COPY (Block)2

OK

NG

P-VOL

PSUS/PSUE (Local)

SSUS/PSUE (Block)

PSUS/PSUE (Local)

SSUS/PSUE (Block)

OK

NG

P-VOL

PSUS/PSUE (Block)

SSWS (Local)

PSUS/PSUE (Block)

SSWS (Local)

NG

OK

S-VOL

Notes:
  1. The pair status and I/O mode after failure depends on the requirement of the pair. For details, see Server I/Os and data mirroring with blocked quorum disk or without quorum disk volumes.
  2. The P-VOL might change to PSUE (Local) and the S-VOL might change to PSUE (Block) if a failure occurred in an external storage system immediately after the pair status changed to COPY.

SIMs

  • Primary storage system: 21D0xy, 21D2xx, DD2xyy, DEF0zz, EF5xyy, EFD000, FF5xyy
  • Secondary storage system: 21D0xy, 21D2xx, DD2xyy, DEF0zz, EF5xyy, EFD000, FF5xyy
  1. Recover the external storage system. For details, contact the vendor.
  2. Resynchronize or re-create GAD pairs if they are suspended by a failure.
    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.