Recovering or replacing a hard disk

NAS Platform and Unified Storage Series 4000 Hardware Reference

Part Number

Some hard disk drive failures require disk replacement, others only require performing a recovery process. Use the recovery process to help ensure that all partitions are recovered before proceeding with any further disk recovery or replacement procedures. Unless you are certain the hard disk has failed, perform a disk recovery.

Important: Do not attempt to replace or recover a hard disk without the assistance of Hitachi Vantara Customer Support. For the latest procedure, please refer to Support Connect article How_to_Replace_a_Chassis_Hard_Disk_in_an_HNAS_Gateway_Node (which is only visible to Service Partners and Employees).

Hard disks can fail for a number of reasons, including corrupt sectors or erroneous blocks of data. Typically, the RAID controller handles these types of errors and they do not cause the server to fail.

More serious errors may cause a disk failure, causing one or both hard disks to fall out of the RAID. Should one partition of a disk fail, attempt a disk recovery. If a partition fails repeatedly, replace the hard disk. If all the partitions fall out of RAID, replace the failed drive.

When removing a hard disk, take extreme care to only press one HDD lever. The push button latch mechanisms are close together and, if not careful, both latches can easily be depressed at one time. This causes an immediate loss of access.
Important: Before you consider replacing a hard disk drive, be sure you understand the following points:
  • Failed hard disks are hot-swappable, so a failed hard disk can be replaced without shutting down the server. However, there are serious risks in trying to swap a drive that is not failed.
  • Do not assume that because the red LED is illuminated that a drive is faulty. Under a RAID rebuild/recovery, the red LED would be illuminated. If the drive is failed and needs replacing, you can remove it from the server.
  • Do not replace a drive that has not actually failed. If the disk shows signs of failure, shut down the server before replacing the drive and restarting the server.
  • There should be no reason to pull out a hard drive while it is in a known good configuration, and doing so can potentially lead to data corruption.
  • Unless you are certain the hard disk has failed, perform a disk recovery.
  • Disk redundancy is unsupported while the disk is removed from the server.
  • The new disk does not have to be the same capacity as the disk that is being replaced.
Warning: It is strongly recommended to perform disk replacement procedures during a maintenance window in order to minimise risk of any disruption caused by the procedure and to allow for the movement of EVSs and other unexpected events that may occur.