Finding and sparing bad tracks and sectors – HP NonStop G-Series User Manual
Page 158
Performing Routine Disk Operations
Guardian User’s Guide — 425266-001
9- 12
Finding and Sparing Bad Tracks and Sectors
1. Check for bad sectors and checksum errors on $DATA01:
-> INFO DISK $DATA01, BAD
2. Log on as a super-group user (255,
n
), enter SCF, and logically remove $DATA01-
M from the system:
-> STOP DISK $DATA01-M
-> STOP DISK $DATA01-MB
3. Physically remove the $DATA01-M disk. Put it on a storage shelf.
4. Mount a previously formatted disk.
5. Start the newly installed disk pack from the primary of $DATA01 so that the new
pack becomes the mirror disk of $DATA01:
-> START DISK $DATA01
SCF prompts you to start a revive operation. Enter Y if you want to continue.
To check the progress of the start operation, enter:
-> STATUS DISK $DATA01, DETAIL
When the START DISK operation finishes, the mirror device is in the STARTED state.
Finding and Sparing Bad Tracks and Sectors
When a disk pack is initially formatted, a fixed number of sectors are reserved at the end
of each cylinder as spares. This number varies depending on the type of disk. These
spare sectors are used only if defective sectors are found on the cylinder.
Sparing sectors is the process of assigning alternate sectors from the available spare
sectors to be used in place of defective sectors, removing associated unspared bad sector
entries from the sector information table (if necessary), and creating entries in the added
defect map. You will only need to spare defective sectors that were not automatically
spared by the formatting operation.
1. List all of the defective sectors on the disk to determine which sectors, if any, need
to be spared:
> SCF
-> INFO DISK $disk, BAD
SCF displays a listing that gives you the logical cylinder, head, and sector address of
any bad sectors. If there are no bad sectors, there is no need to continue with this
procedure.
2. Make sure you are logged on as a super-group user (255,
n
).
3. Stop all other processing on the disk.
STORAGE - Bad Sector Information DISK\ALM171.$DATA01
No bad sectors found.