IBM Redbooks ServeRAID-MR10i, User Manual

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B-4 Glossary of Terms and Abbreviations
is a versatile controller that provides the backbone of both server and
high-end workstation environments. Each port on the RAID controller
supports SAS devices and/or SATA II devices.
SAS device Any device that conforms to the SAS standard and is attached to the
SAS bus by a SAS cable. This includes SAS storage adapters
(host adapters) and SAS peripherals.
SATA Acronym for Serial Advanced Technology Attachment. A physical
storage interface standard, SATA is a serial link that provides point-to-
point connections between devices. The thinner serial cables allow for
better airflow within the system and permit smaller chassis designs.
SMP Acronym for Serial Management Protocol. SMP enables communicates
topology management information directly with an attached SAS
expander device. Each PHY on the controller can function as an SMP
initiator.
SSD Acronym for Solid State Devices. A Solid State Device uses solid-state
memory to store data. They have no moving parts and are faster and
more reliable than hard disk drives (HDDs).
SSP Acronym for 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 Acronym for Serial Tunneling Protocol. STP enables communication with
a SATA II device through an attached expander. Each PHY on the SAS
controller can function as an STP initiator.
stripe size The total disk space consumed by a stripe not including a parity disk. For
example, consider a stripe that contains 64 Kbytes of disk space and has
16 Kbytes of data residing on each disk in the stripe. In this case, the
stripe size is 64 Kbytes and the stripe element size is 16 Kbytes. The
stripe depth is four (four physical disks in the stripe). You can specify
stripe sizes of 8 Kbytes, 16 Kbytes, 32 Kbytes, 64 Kbytes, or 128 Kbytes
for each virtual disk. A larger stripe size produces improved read
performance, especially if most of the reads are sequential. For mostly
random reads, select a smaller stripe size.
striping Disk striping writes data across two or more disks. Each stripe spans two
or more disks but consumes only a portion of each disk. Each disk,
therefore, may have several stripes. The amount of space consumed by