Compaq HSZ80 manual Guidelines for Partitioning Storagesets Disk Drives

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An unpartitioned storage unit has more capacity than a partition that uses the whole unit because each partition requires five blocks of administrative metadata. Thus, a single disk unit that contains one partition can store n-5 blocks of user or application data.

See “Partitioning a Storageset or Disk Drive,” page 4–10,for information on manually partitioning a storageset or single-disk unit.

Guidelines for Partitioning Storagesets and

Disk Drives

Keep these points in mind as you plan your partitions:

■You can create up to eight partitions per storageset or disk drive.

■All of the partitions on the same storageset or disk drive must be addressed through the same target ID (host-addressable SCSI ID). Thus, if you set a preferred controller for that ID, all the partitions in that storageset will inherit that preferred controller. This ensures a transparent failover of devices should one of the dual-redundant controllers fail.

■Partitions cannot be combined into storagesets. For example, you cannot divide a disk drive into three partitions, then combine those partitions into a RAIDset.

■Partitioned storagesets cannot function in multiple bus failover dual-redundant configurations. Because they are not supported, you must delete your partitions before configuring the controllers for multiple bus failover.

■Once you partition a container, you cannot unpartition it without reinitializing the container.

■Just as with storagesets, you do not have to assign unit numbers to partitions until you are ready to use them.

Compaq HSZ80 Array Controller ACS Version 8.3 Configuration and CLI Reference Guide