Recovering from a primary site failure (GAD+UR)

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

When a failure occurs at a primary site, the status of the GAD pair changes to PSUE/SSWS. In this case, delta resync is automatically performed, and the pair statuses change as shown in the following table.

Before failure			After failure
Pair type	Pair status		Pair type	Pair status
Pair type	P-VOL	S-VOL	Pair type	P-VOL	S-VOL
GAD pair	PAIR	PAIR	GAD pair	PSUE*	SSWS
UR pair	PAIR	PAIR	UR delta resync pair	PSUE*	SSUS
UR delta resync pair	(VSP One B20 series) PSUE* (VSP One B85) PSUS*	SSUS	UR pair	From COPY to PAIR	From COPY to PAIR
* Pair status after the primary site is turned on.

If a failure occurs, the UR delta resync pair changes to a UR pair, and copying from the GAD S-VOL to the UR S-VOL starts. When the UR pair copying is completed, the status of the P-VOL and the status of the S-VOL of the UR pair change to PAIR.

Overview of failure recovery

Remove the failure on the P-VOL.
A 3DC delta resync configuration is automatically re-created.
Reverse the P-VOL and the S-VOL, and then resynchronize the GAD pairs (swap resync) on the storage system at the GAD secondary site.
Command example:
```
pairresync -g oraHA -swaps -IH1
```
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.

The volume on the primary storage system changes to an S-VOL, and the volume on the GAD secondary storage system changes to a P-VOL.

Confirm that the GAD P-VOL and S-VOL pair statuses change to PAIR.

Command example:

pairdisplay -g oraHA -fxce -IH0
Group PairVol(L/R) (Port#,TID, LU),Seq#,LDEV#.P/S,Status,Fence, %,P-LDEV# M CTG JID AP EM E-Seq# E-LDEV# R/W
oraHA dev1(L) (CL1-A-0, 0, 0)811111 2222.P-VOL PAIR NEVER , 100 4444 - - 0 - - - - L/M
oraHA dev1(R) (CL1-C-0, 0, 0)822222 4444.S-VOL PAIR NEVER , 100 2222 - - 0 - - - - L/M

pairdisplay -g oraHA -fxce -IH1
Group PairVol(L/R) (Port#,TID, LU),Seq#,LDEV#.P/S,Status,Fence, %,P-LDEV# M CTG JID AP EM E-Seq# E-LDEV# R/W
oraHA dev1(L) (CL1-C-0, 0, 0)822222 4444.S-VOL PAIR NEVER , 100 2222 - - 0 - - - - L/M
oraHA dev1(R) (CL1-A-0, 0, 0)811111 2222.P-VOL PAIR NEVER , 100 4444 - - 0 - - - - L/M

Keep updating I/O from the server to the P-VOL or S-VOL of the GAD pair for about two minutes.

Confirm that the UR delta resync P-VOL pair status is PSUS.

Command example:

pairdisplay -g oraREMOTE -fxce -IH0
Group PairVol(L/R) (Port#,TID, LU),Seq#, LDEV#.P/S,Status,Fence, %, P-LDEV# M CTG JID AP EM E-Seq# E-LDEV# R/W
oraDELTA dev2(L) (CL1-A-1, 0, 1) 811111 2222. P-VOL PSUS ASYNC ,0 6666 - 0 0 - - - - -/-
oraDELTA dev2(R) (CL1-A-1, 0, 1) 844444 6666. S-VOL SSUS ASYNC ,0 2222 - 0 0 - - - -  -/-

Confirm that the mirror status of the journal of the UR delta resync pair is PJNS.

Command example:

pairdisplay -g oraREMOTE -v jnl -IH0
JID MU CTG JNLS AP U(%) Q-Marker Q-CNT D-SZ(BLK) Seq# Num LDEV#
000 1 1 PJNS 4 21 43216fde 30 512345 62500 1 39321

Confirm that no failure SIMs are displayed.
Reverse the GAD P-VOL and the S-VOL if necessary.
For instructions, see Reversing the GAD P-VOL and S-VOL (GAD+UR).

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.