3.3 Maintaining the Hard Disks of Oracle Exadata Storage Servers

Every Oracle Exadata Storage Server in Oracle Exadata Rack has a system area, which is where the Oracle Exadata System Software system software resides. In Oracle Exadata X7 and later systems, two internal M.2 devices contain the system area. In all other systems, the first two disks of Oracle Exadata Storage Server are system disks and the portions on these system disks are referred to as the system area.

In Oracle Exadata X7 and later systems, all the hard disks in the cell are data disks. In systems prior to Oracle Exadata X7, the non-system area of the system disks, referred to as data partitions, is used for normal data storage. All other disks in the cell are data disks.

Starting in Oracle Exadata System Software release 11.2.3.2.0, if there is a disk failure, then Oracle Exadata System Software sends an alert stating that the disk can be replaced, and, after all data has been rebalanced out from that disk, turns on the blue OK to Remove LED for the hard disk with predictive failure. In Oracle Exadata System Software releases earlier than 11.2.3.2.0, the amber Fault-Service Required LED was turned on for a hard disk with predictive failure, but not the blue LED. In these cases, it is necessary to manually check if all data has been rebalanced out from the disk before proceeding with disk replacement.

Starting with Oracle Exadata System Software release 18.1.0.0.0 and Oracle Exadata X7 systems, there is an additional white Do Not Service LED that indicates when redundancy is reduced to inform system administrators or field engineers that the storage server should not be powered off for services. When redundancy is restored, Oracle Exadata System Software automatically turns off the Do Not Service LED to indicate that the cell can be powered off for services.

For a hard disk that has failed, both the blue OK to Remove LED and the amber Fault-Service Required LED are turned on for the drive indicating that disk replacement can proceed. The behavior is the same in all releases. The drive LED light is a solid light in Oracle Exadata System Software releases 11.2.3.2.0 and later; the drive LED blinks in earlier releases.

Note:

Oracle Exadata Rack is online and available while replacing the Oracle Exadata Storage Server physical disks.

This section contains the following topics:

• Monitoring the Status of Hard Disks
  You can monitor the status of a hard disk by checking its attributes with the CellCLI LIST PHYSICALDISK command.
• Replacing a Hard Disk Due to Disk Failure
  
• Replacing a Hard Disk Due to Disk Problems
  You may need to replace a hard disk because the disk is in warning - predictive failure status.
• Replacing a Hard Disk Due to Bad Performance
  A single bad hard disk can degrade the performance of other good disks. It is better to remove the bad disk from the system than let it remain.
• Replacing a Hard Disk Proactively
  Exadata Storage software has a complete set of automated operations for hard disk maintenance, when a hard disk has failed or has been flagged as a problematic disk. But there are situations where a hard disk has to be removed proactively from the configuration.
• Moving All Drives to Another Exadata Storage Server
  It may necessary to move all drives from one Exadata Storage Server to another Exadata Storage Server.
• Repurposing a Hard Disk
  You may want to delete all data on a disk, and then use the disk for another purpose.
• Removing and Replacing the Same Hard Disk
  What happens if you accidentally remove the wrong hard disk?
• Re-Enabling a Hard Disk That Was Rejected
  If a physical disk was rejected because it was inserted into the wrong slot, you can re-enable the disk.