Instruction Manual

172 Glossary

Spanning

The method by which nested RAID levels (such as RAID 10, 50, and 60) are

constructed from multiple sets of basic, or single RAID levels. For example, a

RAID 10 is made up of multiple sets of RAID 1 arrays where each RAID 1 set is

considered a span. Data is then striped (RAID 0) across the RAID 1 spans to

create a RAID 10 virtual disk. The same concept holds true for RAID 50 and 60

where multiple sets of RAID 5 or RAID 6 can be combined together

with RAID levels.

Spare

A physical disk available to replace another physical disk in case that physical

disk fails.

SSD

Solid-state Disk. SSDs are storage devices that use solid-state memory to store

data as opposed to traditional rotational hard drives. SSDs can be made to use

either the SAS or SATA protocol.

SSP

Serial SCSI Protocol. SSP enables communication with other SAS devices.

Each

PHY on the SAS controller can function as an SSP initiator or SSP target.

STP

Serial Tunneling Protocol, STP, enables communication with a SATA device

through an attached expander.

Each PHY on the SAS controller can function

as an STP initiator.

Stripe Element

A stripe element is the portion of a stripe that resides on a single physical disk.