Follow these general guidelines for configuring disk drives. In addition to the following general guidelines, more specific guidelines for configuring disk drives in data-intensive environments and attribute-intensive environments follows:
Configure additional drives on each host adapter without degrading performance (as long as the number of active drives does not exceed SCSI standard guidelines).
Use Online: DiskSuite or Solstice DiskSuite to spread disk access load across many disks. See "Using Solstice DiskSuite or Online: DiskSuite to Spread Disk Access Load"" later in this chapter.
Use the fastest zones of the disk when possible. See "Using the Optimum Zones of the Disk"" later in this chapter.
Keep these rules in mind when configuring disk drives in data-intensive environments:
Configure for a sequential environment.
Use disks with the fastest transfer speeds (preferably in stripes).
Configure one RAID device (logical volume or metadisk) for every three active version 3 clients or one device for every four to five version 2 clients.
Configure one drive for every client on Ethernet or Token Ring.
When configuring disk drives in attribute-intensive environments:
Configure with a larger number of smaller disks, which are connected to a moderate number of SCSI host adapters (such as a disk array).
Configure four to five (or up to eight or nine) fully active disks per fast SCSI host adapter Using smaller disk drives is much better than operating with one large disk drive.
Configure at least one disk drive for every two fully active clients (on any type of network.)
Configure no more than eight to ten fully active disk drives for each fast/wide SCSI host adapter.