13. Reverse the P-VOL and the S-VOL if necessary.
Related topics
• I/O modes on page 1-12
•
Failure locations on page 6-3
• Reversing the P-VOL and S-VOL on page 6-51
•
Configuring the quorum disk on page 5-6
• Discontinuing a global-active device environment on page 5-23
Reversing the P-VOL and S-VOL
During disaster recovery operations, P-VOLs are changed to S-VOLs and S-
VOLs to P-VOLs to reverse the flow of data from the secondary site to the
primary site to restore the primary site. When normal operations are resumed
at the primary site, the direction of copy is changed again so that the original
P-VOLs become primary volumes again and the original S-VOLs become
secondary volumes again with data flowing from the primary site to the
secondary site.
Steps to reverse data flow
1. Using the alternate path software, stop I/O from the server to P-VOLs in
the secondary storage system.
Continue to the next step even if the alternate path cannot be deleted.
2. Confirm that the P-VOL and the S-VOL have been reversed.
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)311111 2222.S-VOL PAIR
NEVER , 100 4444 - - 0 - - - - L/M
oraHA dev1(R) (CL1-C-0, 0, 0)322222 4444.P-VOL PAIR
NEVER , 100 2222 - - 0 - - - - L/M
3. At the primary storage system, change the pair statuses of the S-VOLs to
SSWS to suspend the pairs (swap suspension).
pairsplit -g oraHA -d devX -RS -IH0
4. At the secondary storage system, reverse the P-VOL and the S-VOL, and
then resynchronize the pairs (swap resync).
pairresync -g oraHA -d devX -swaps -IH0
5. Confirm that the P-VOL and the S-VOL pair statuses change to PAIR
(Mirror (RL)).
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)311111 2222.P-VOL PAIR
NEVER , 100 4444 - - 0 - - - - L/M
oraHA dev1(R) (CL1-C-0, 0, 0)322222 4444.S-VOL PAIR
NEVER , 100 2222 - - 0 - - - - L/M
Disaster recovery of global-active device
6-51
Hitachi Virtual Storage Platform G1000 Global-Active Device User Guide
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