Intel SRCU31, User Manual

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36 Intel RAID SRCU31 Users Guide
Table 10. Additional Operational States
State Description
OK State The disk array is fully operational when in the OK state. All redundant
information is present, that is, a hard disk drive can fail without impairing the
functionality of the disk array. This is the normal state of a disk array.
Methods for Hard Disk Drive Replacement
The Intel RAID Controller SRCU31 and the Intel RAID Controller SRCU31 firmware offer a
variety of methods to replace a defective hard disk drive. When to use them depends on the
physical environment of the server. With some servers the hard disk drives are mounted into the
server enclosure. They are not removable. With other servers there is an intelligent backplane (for
example, SAF-TE) and which hosts a number of hard disk drives with a Single Connector
Attachment (SCA). Another type of server uses the hard disk drive in a hot pluggable disk carrier.
These carriers are often unintelligent and do not communicate with the Intel RAID Controller
SRCU31 or server, though, they can display the hard disk drive’s temperature or the status of its
built-in fan. Table 11 contrasts the various hard disk drive replacement options.
Table 11. Hard Disk Drive Replacement Options
Manual Hot Plug
Auto Hot Plug Automatic Replacement
with Hot Fix Drive
Typical
Server
Environment
Low Cost.
Hard Disk Drives are
physically mounted in the
server enclosure and are not
removable.
Additional cost for external
enclosure, cables,
backplanes, etc.
Hard Disk Drives are
removable in an intelligent or
non-intelligent subsystem.
The subsystem complies
with one of the following
enclosure standards:
“SAF-TE” (SCSI Accessed
Fault Tolerant Enclosures)
“SES” (SCSI Enclosure
Services)
“Intelligent Fault Bus” (former
DEC™ fault bus)
Non-Intelligent subsystems
using hot pluggable disk
carriers.
Low cost.
High availability.
The Intel RAID Controller
SRCU31 has a spare drive
available at all times. Should
one hard disk drive of an
array fail, the spare drive
(hot fix drive) is automatically
built into the array.
continued