Intel SRCU31, User Manual

Page: 103 / 182

Storage Console 103
Today’s modern subsystems are either using SAF-TE (SCSI Accessed Fault Tolerant Enclosures)
or SES (SCSI Enclosure Services) as communication links to the controller. These intelligent
subsystems are normally built on so-called backplanes, which host hard disk drives equipped with
SCA (Single Connector Attachment) connectors. The backplane has dedicated electronics with
microprocessor and firmware which allows intelligent communication between the
subsystem/backplane and the Intel RAID Controller SRCU31. Through this channel the subsystem
can report its temperature and the power supply status to the Intel RAID Controller SRCU31. The
major objective of SAF-TE or SES is auto hot plug. In contrast to hot plug, auto hot plug allows a
defective drive to be simply removed from the subsystem and the replacement unit installed in its
place. Both the Intel RAID Controller SRCU31 and the subsystem control this process so that
problems on the SCSI/FC-AL bus are eliminated and the rebuilding of the missing data is initiated
automatically. No further user interaction is necessary.
Non-Intelligent Enclosures
Since SAF-TE or SES subsystems are expensive, Intel RAID Controller SRCU31 integrates
functionality which allows for the control of up to 16 non-intelligent enclosures with up to 15 hard
disk drives each, and provides for auto hot plug.
In the example in Figure 38 one subsystem is defined. The hard disk drives with their disk shuttles
could also be mounted directly into the server enclosure. The term enclosure in this case is a
definition set, which includes all hard disk drives which should be auto hot pluggable.
Figure 38. Select Enclosure