When GAD configuration is complete, you can start creating GAD pairs. When a pair is created, the P-VOL LDEV ID is set as the S-VOL's virtual LDEV ID. When the paircreate operation completes, the pair status becomes PAIR, and the P-VOL and S-VOL can accept I/O from the host. When a pair is deleted, the S-VOL's virtual LDEV ID is deleted, and the GAD reserve attribute remains set on the S-VOL.
If you create a GAD pair by using VSM auto-configuration, the serial number and model of the P-VOL is automatically set as the virtual serial number and virtual model of the S-VOL. AUTO_VIRTUAL_STORAGE is set to YES on the S-VOL. When you delete a GAD pair created by VSM auto-configuration, the virtual serial number and virtual model of the S-VOL are not deleted. AUTO_VIRTUAL_STORAGE remains set to YES on the S-VOL. For details about the requirements for using VSM auto-configuration, see Creating GAD pairs.
- When you create a GAD pair, make sure that the available pool capacity for Dynamic Provisioning below the warning threshold is more than the capacity of the secondary volume. If you create a GAD pair at the secondary storage system when the available pool capacity below the warning threshold is less than the capacity of the secondary volume, SIM (SIM=620xxx, where xxx is the pool ID) is issued (the used capacity exceeds the warning threshold).
- You cannot create a GAD pair by using instances (100 and 101) for confirming the virtual LDEV IDs. To create a GAD pair, use instances (0 and 1) for operating storage systems.
- If you change the ALUA settings for a volume that the server has already recognized, shut down the server before creating a GAD pair. After creating a GAD pair, start the server, and then enable the server to recognize the volume.
- If you change the ALUA settings while the server is online, the server might not recognize the changes in the ALUA settings or might perform abnormally.
- When creating a pair, you can optionally set I/O preference mode when remote path failed. For more information, see Creating a pair by setting I/O preference mode when remote path failed.
Creating a GAD pair using VSM auto-configuration
Creating a GAD pair using VSM manual configuration
Procedure
Specify 0 for the quorum disk ID and specify 2 for the consistency group ID to create a GAD pair.
paircreate -g oraHA -fg never 2 -vl -jq 0 -IH0
To register GAD pairs to a consistency group, specify the -fg option when creating the pair. If you create a pair and do not specify a consistency group ID, the ID for an unused consistency group in the storage system will be automatically assigned.
The following example shows a command used to create a GAD pair without registering the pair to a consistency group:
paircreate -g oraHA -f never -vl -jq 0 -IH0
Check command and output examples
Confirm that a GAD pair is created.
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
Confirm that the copy progress reaches 100%.