HP NonStop G-Series - Manual (Page 155)

Performing Routine Disk Operations
Guardian User’s Guide — 425266-001
9 -9
Altering the Current Path to a Dual-Ported Disk
Altering the Current Path to a Dual-Ported Disk
To test alternate paths to a dual-ported disk, you alter the current path:
1. Make sure you are logged on as a super-group user (255, n ).
2. Enter the following form of the SCF SWITCH command:
-> SWITCH $disk { -P | -B | -M | -MB }
You must designate whether you want the primary (-P), backup (-B), mirror (-M), or
mirror backup (-MB) controller path to become the current path to the disk. The
path you specify then becomes the path of first choice when a user process needs to
access the disk.
Example
In the partial STATUS DISK shown below, the STARTED states indicate that the
primary and mirror paths of $AMBER are active:
Removing Half of a Mirrored Disk
You might need to physically remove half of a mirrored disk to use for backups or other
purposes.
1. Make sure you are logged on as a super-group user (255, n ).
2. Bring the application to a quiet state to ensure the integrity of the files. This does not
require that application programs close their files, but that the current transactions
are completed normally.
3. If the target disk is protected by the Transaction Management Facility (TMF)
subsystem, disable it from the TMF subsystem before performing this operation.
4. Issue an SCF STOP DISK command.
SCF STOP DISK is valid only for physically demountable mirrored disks, and it is
rejected if either disk of the mirrored disk is already down.
5. Determine whether any unspared bad sectors exist on the disk:
-> INFO DISK $disk, BAD
1-> STATUS DISK $AMBER
STORAGE - Status DISK \SHARK.$AMBER
LDev Primary Backup Mirror MirrorBackup Primary Backup
PID PID
6 STARTED STARTED STARTED STARTED 0,268 1,265
Note. If the target disk contains any SQL file, see your operations manager or database
administrator before issuing an SCF STOP DISK command on the target disk.