Removing an Underperforming Physical Disk

A bad physical disk can degrade the performance of other good disks. You should remove the bad disk from the system.

To remove a physical disk after identifying the bad disk:

Illuminate the physical drive service LED to identify the drive to be replaced:
```
cellcli -e 'alter physicaldisk disk_name serviceled on'
```
In the preceding command, disk_name is the name of the physical disk to be replaced, such as 20:2.
Identify all grid disks on the bad disk, and direct Oracle ASM to stop using them:
```
ALTER DISKGROUP diskgroup_name DROP DISK asm_disk_name
```
Ensure that the blue "OK to Remove" LED on the disk is lit.
Query the V$ASM_DISK_STAT view to ensure that the Oracle ASM disks affected by the bad disk were dropped successfully.
Remove the bad disk.

An alert is sent when the disk is removed.
When a new disk is available, install it in the system. The cell disks and grid disks are created automatically on the new physical disk.
Confirm that the disk is online and its status is NORMAL:
```
CellCLI> LIST PHYSICALDISK WHERE name=28:5 ATTRIBUTES status
```
When you replace a physical disk, the RAID controller must acknowledge the replacement disk before you can use it. Acknowledgment is quick.