Maintaining the Compute Servers

You do not need to shut down a compute server in Recovery Appliance to repair the physical disks. No downtime of the rack is required; however, individual servers might require downtime, and you might need to take them out of the cluster temporarily.

An LSI MegaRAID SAS 9261-8i disk controller manages the disk drives in each compute server. The disks have a RAID-5 configuration. Each compute server has four disk drives. One virtual drive comprises the RAID set.

Verifying the RAID Status of a Compute Server

Oracle recommends that you periodically verify the status of the compute server RAID devices. The impact is minimal. In contrast, the impact of corrective action varies depending on the specific issue uncovered, and can range from simple reconfiguration to an outage.

To verify the RAID status:

Check the current disk controller configuration:
```
# /opt/MegaRAID/MegaCli/MegaCli64 -AdpAllInfo -aALL | grep "Device Present" -A 8

                Device Present
                ================
Virtual Drives    : 1 
  Degraded        : 0 
  Offline         : 0 
Physical Devices  : 5 
  Disks           : 4 
  Critical Disks  : 0 
  Failed Disks    : 0 
```
Verify that the output shows one virtual drive, none degraded or offline, five physical devices (one controller + four disks), four disks, and no critical or failed disks.

If the output is different, then investigate and correct the problem. Degraded virtual drives usually indicate absent or failed physical disks. Replace critical disks and failed disks immediately. Otherwise, you risk data loss if the number of working disks in the server is less than the number required to sustain normal operation.

Check the current virtual drive configuration:

# /opt/MegaRAID/MegaCli/MegaCli64 CfgDsply -aALL | grep "Virtual Drive:";    \
/opt/MegaRAID/MegaCli/MegaCli64 CfgDsply -aALL | grep "Number Of Drives";  \
/opt/MegaRAID/MegaCli/MegaCli64 CfgDsply -aALL | grep "^State" 

Virtual Drive                 : 0 (Target Id: 0)
Number Of Drives              : 4
State                         : Optimal

Verify that virtual device 0 has four drives, and the state is Optimal. If the output is different, then investigate and correct the problem.

Check the current physical drive configuration:
```
# /opt/MegaRAID/MegaCli/MegaCli64 -PDList -aALL | grep "Firmware state"
Firmware state: Online, Spun Up
Firmware state: Online, Spun Up
Firmware state: Online, Spun Up
Firmware state: Online, Spun Up
```
Ensure that all drives are Online, Spun Up. If the output is different, then investigate and correct the problem.

If the output is different, then investigate and correct the problem. Degraded virtual drives usually indicate absent or failed physical disks. Replace critical disks and failed disks immediately. Otherwise, you risk data loss if the number of working disks in the server is less than the number required to sustain normal operation.