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Hard Drive Installation and Replacement

Each drive on a SCSI bus must have a unique ID value in the range 0 to 15 (except ID 7, which is reserved for controller use). This SCSI ID value is set automatically on hot-pluggable drives in ProLiant servers and storage systems, but values for other drives must be set manually.

•Do not terminate the drives. The internal cabling in ProLiant servers provides the required termination of the SCSI bus.

•Do not use drives of different capacity in the same array. The excess capacity of larger drives cannot be used by the array and is wasted.

•Do not use hot-pluggable drives on the same SCSI bus as non-hot-pluggable drives.

Drives can be of the Ultra2, Ultra160 (Ultra3), or Ultra320 (Ultra4) type.

General Information About Hard Drive Failure

When a hard drive fails, all logical drives that are in the same array are affected. Each logical drive in an array may be using a different fault-tolerance method, so each logical drive can be affected differently.

•RAID 0 configurations cannot tolerate drive failure. If any physical drive in the array fails, all non-fault-tolerant (RAID 0) logical drives in the same array will also fail.

•RAID 1+0 configurations can tolerate multiple drive failures as long as no failed drives are mirrored to one another.

•RAID 5 configurations can tolerate one drive failure.

HP Smart Array 641/642 Controller User Guide

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