SCF Reference Manual for the Storage Subsystem (G06.24+, H06.03+)

Managing Magnetic Disks
SCF Reference Manual for the Storage Subsystem—529937-007
7-27
Changing the Active Path for a Magnetic Disk
Changing the Active Path for a Magnetic Disk
The SWITCH DISK Command (page 14-156) designates the active path to a disk,
determines whether the -P or -B path is active and, if the disk is mirrored, whether the
-M or -MB path is active.
You should configure the -P and -M paths to be active because they are on opposite
ServerNet fabrics.
Considerations for SWITCH DISK
•
If you attempt to switch the primary and backup paths but the backup path is
unavailable, the paths are not switched.
•
If the specified path is already active, the SWITCH command has no effect.
•
Use the STATUS DISK command to verify the path switch.
•
Switching the path to the backup controller can create a SAC ownership conflict in
G06.10 and earlier RVUs. See Understanding SAC Ownership on page 8-6.
Switching the Active Path for a Disk
1. Display the current status of the disk paths:
-> STATUS $D0201-*
•
The $D0201 disk process is still executing in processor 2.
•
The $D0201 disk is now accessed through SACs in the same PMF CRU.
•
The disk process is now using the backup path to access the primary disk.
•
The mirror path is unaffected by the switch.
•
Both paths now use the Y fabric.
STORAGE - Status DISK \WAGER.$D0201-*
LDev Path Status State Substate Primary Backup
PID PID
104 PRIMARY ACTIVE STARTED 2,107 3,35
104 BACKUP INACTIVE STARTED 2,107 3,35
104 MIRROR ACTIVE STARTED 2,107 3,35
104 MIRROR-BACKUP INACTIVE STARTED 2,107 3,35