Recovering from a P-VOL failure (LDEV blockade) at the primary site (GAD+UR)

Global Active Device for VSP One Block

Version

10.5.x

Audience

anonymous

Part Number

MK-23VSP1B011-10

ft:lastEdition

2026-05-04

When a failure (LDEV blockade) occurs on a P-VOL at the 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 follows:

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	PSUS	SSUS	UR pair	From COPY to PAIR	From COPY to PAIR

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 (LDEV blockade) on the P-VOL.
If the P-VOL must be formatted for restoration, delete the GAD pair, and then format the P-VOL.
When deleting the GAD pair, first delete the S-VOL of which I/O mode is Local.
Depending on if you performed step 2, re-create the GAD pair, the delta resync UR pair, and the UR pair in that order, or reverse the P-VOL and the S-VOL in the GAD secondary storage system, and then resynchronize the GAD pair.
- If you performed step 2, re-create the GAD pair, the delta resync UR pair, and the UR pair in that order.
  If a failure occurs after the one volume capacity of a GAD pair or UR pair can be expanded, the creation, resync, swap resync, horctakeover, and delta resync operations of the GAD pair or UR 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.
  
  For the GAD pair, first re-create the S-VOL.
  
  If necessary, after executing the command, reverse the P-VOL and S-VOL of the GAD pair.
  
  Command example:
```
paircreate -g oraHA -fg never 2 -vl -jq 0 -IH1
paircreate -g oraDELTA -f async -vl -jp 0 -js 0 -nocsus -IH1
paircreate -g oraREMOTE -f async -vl -jp 0 -js 0 -IH0
```
- If you did not perform step 2, reverse the P-VOL and the S-VOL in the GAD secondary storage system, and then resynchronize the GAD pair (swap resync).
  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.
  
  Command example:
```
pairresync -g oraHA -swaps -IH1
```
  The primary storage system volume becomes the S-VOL, and the GAD secondary storage system volume becomes the 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.