Compaq 3200 manual Replacing a Failed Drive, Spare Drives

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Spare Drives

In the event of a drive failure, if a spare drive is assigned and available, the spare drive acts as an immediate replacement for the failed drive. Data is reconstructed automatically from the remaining drive(s) in the volume and written to the spare drive through the Automatic Data Recovery process. Once the spare drive is completely built, the logical drive again runs at full fault tolerance and is then able to sustain another subsequent drive failure. Note, however, that if another drive fails before the spare drive is completely built, the spare drive cannot prevent failure of the entire logical drive. Also note that it is possible for non-correctable disk errors to prevent completion of the Automatic Data Recovery process (discussed below).

Replacing a Failed Drive

Failed drives in hot-pluggable trays can be removed and replaced while host system and storage system power are both ON. Hot-pluggable drives can also be replaced when the power is OFF. Remember, however, to never turn off an external storage system while the host system power is on. This results in the failure of all drives in the storage system, which would likely compromise your fault tolerance. When a hot-pluggable drive is inserted, all disk activity on the controller is temporarily paused while the drive is spinning up (usually 20 seconds or so). If the drive is inserted while power is ON, in fault-tolerant configurations, recovery of data on the replacement drive begins automatically (indicated by blinking online LED).

Non-hot-pluggable drives should only be replaced while the system power is OFF. On all non-hot-pluggable drives, be sure to check the SCSI ID jumpers to make sure the correct drive is being replaced. To prevent compromising the

fault tolerance, it is imperative that the correct physical drive be replaced.

Also, be sure that the SCSI ID jumpers are set to the same SCSI ID on the replacement drive. The SCSI ID jumpers may be located at different places on different drive models, but it is necessary that the SCSI ID on the replacement drive always be set to the same value as the original failed drive to prevent SCSI ID conflicts that could compromise the fault tolerance.

Compaq Smart Array 3200 Controller Reference Guide