Compaq 3000 - Manual (Page 37)

RAID Array 3000 Controller Shelf
2–4 EK–SMCPQ–UG. C01
From the storage shelf’s perspective, the controller receives the I/O requests from
the host and directs them to the devices. Since the controller processes all the I/O
requests, it eliminates the host-based processing that is typically associated with
reading and writing data to multiple storage devices.
The controller does much more than simply manage I/O requests: it provides the
ability to combine several ordinary disk drives into a single, high-performance
storage unit called a storageset. Storagesets are implementations of RAID tech-
nology, also known as a “Redundant Array of Independent Disks”. Every stor-
ageset shares one important feature: whether it uses two disk drives or 12, each
storageset looks like a single storage unit to the host.
You create storage units by combining disk drives into storagesets such as stripe-
sets, RAIDsets, and mirrorsets, or by presenting them to the host as single-disk
units (see Figure 2–3).
Figure 2–3 Logical Units Created from Storagesets, Partitions, and Disk
Drives
Logical
Unit
Logical
Unit
Logical
Unit
Logical
Unit
Mirrorset
Partitioned
Storageset
Stripset
Partitioned
Disk Drive
Striped
Mirrorset
Raidset
Disk Drives