Replacing a Disk Controller Battery Backup Unit

The disk controller battery backup unit (disk controller BBU) resides on a drive tray in the compute and storage servers. You can replace the disk controller BBU without downtime. The following procedures describe how to replace the disk controller BBU:

Replacing a Disk Controller BBU on a Compute Server

The following procedure describes how to replace a disk controller BBU on a compute server:

Drop the disk controller BBU for replacement:

# /opt/oracle.cellos/compmon/exadata_mon_hw_asr.pl -drop_bbu_for_replacement

Verify that the disk controller BBU has been dropped for replacement:

# /opt/oracle.cellos/compmon/exadata_mon_hw_asr.pl -list_bbu_status

BBU status: dropped for replacement.

Replace the disk controller BBU by releasing the drive caddy and slowly pulling out the tray, and then sliding the replacement tray into the slot. The disk controller BBU is located in slot 7.

Verify that the new disk controller BBU has been detected. It may take several minutes.

# /opt/oracle.cellos/compmon/exadata_mon_hw_asr.pl -list_bbu_status

BBU status: present

Verify that the current logical disk drive cache policy uses writeback mode.

# /opt/MegaRAID/MegaCli/MegaCli64 -ldinfo -lall -a0 | egrep         \
'Default Cache|Current Cache'
Default Cache Policy: WriteBack, ReadAheadNone, Direct, No Write Cache if
Bad BBU
Current Cache Policy: WriteBack, ReadAheadNone, Direct, No Write Cache if
Bad BBU

If the cache policy is not writeback, then go to step 6. Otherwise, go to step 7.

Verify that the battery state is Operational. This step is required only when the cache policy output from step 5 is not writeback.
```
# /opt/MegaRAID/MegaCli/MegaCli64 -adpbbucmd -getbbustatus -a0|grep Battery
BatteryType: iBBU08
Battery State : Operational
Battery Pack Missing : No
Battery Replacement required : No
```
If the battery state is not Operational, then investigate and correct the problem.
Perform battery checks as described in My Oracle Support Doc ID KB176594. If the checks return unexpected results, then refer to the note for additional information and instructions.
(Optional) Use the exachk tool to verify the health of the system. See My Oracle Support Doc ID KB74841.

Replacing a Disk Controller BBU on a Storage Server

To replace a disk controller BBU on a storage server:

Drop the disk controller BBU for replacement using the following command:
```
# cellcli -e alter cell bbu drop for replacement
```
Verify that the disk controller BBU has been dropped for replacement using the following command:
```
# cellcli -e list cell attributes bbustatus

BBU status: dropped for replacement.
```
Replace the disk controller BBU by releasing the drive caddy and slowly pulling out the tray, and then sliding the replacement tray into the slot. The disk controller BBU is located in rear slot 1 of the server.
Verify that the disk controller BBU battery state is operational.
```
# cellcli -e list cell attributes bbustatus

BBU status: normal
```
Perform battery checks as described in My Oracle Support Doc ID KB176594. If the checks return unexpected results, then refer to the note for additional information and instructions.
(Optional) Use the exachk tool to verify the health of the system. The tool is available in My Oracle Support Doc ID KB74841.