Toshiba Magnia 3135R, Руководство пользователя

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Connecting Hardware Devices
Small Computer Systems Interface (SCSI)
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The device at the end of the cable must be terminated. LVDS devices generally do not
have termination capabilities. Non-LVDS devices generally are terminated through a
jumper or resistor pack. If your device does not have a termination jumper or resistor
pack, you must add a terminator to the end of the cable.
The hot-swap backplane in the Magnia 3135R system provides termination for the LVD
SCSI bus.
Downgraded Server Operation
If your server is equipped with a RAID controller for data redundancy and one of the hard
disk drives in the array fails, the system will go into a "downgraded operational state" and
continue to run. If, in addition, the server has a specified spare hard disk drive (hot spare)
in reserve, the server can run in a "downgraded operational state" with up to two failed
hard disk drives.
The MegaRAID
®
controller installed in Toshiba Magnia 3135R servers supports the
following standard RAID levels:
❖
RAID 0 (Striping)
❖
RAID 1 (Disk Mirroring)
❖
RAID 5 (Disk Striping with Distributed Parity)
❖
RAID 10 (Mirroring and Disk Striping)
RAID 0 - Disk Striping
Striping, also referred to as a Stripe set, chains multiple drives into a single logical
storage unit. Striping partitions each drive’s storage space into stripes, or data chunks,
may be as small as one sector (512 bytes) or as large as several megabytes. The stripes
are interleaved so that the combined storage space of the array comprises alternate
stripes from each hard disk drive. The end result is an even distribution of storage space
across the entire set of drives in the array.
The type of operating system installed on the server determines whether large or small
stripes are used in the array. Although disk striping fully utilizes I/O system capability and
improves overall disk performance,
it does not provide for data redundancy .
RAID 1 - Disk Mirroring
Data written to one hard disk drive is simultaneously written to another hard disk drive. If
one disk fails, the other disk can be used to run the system and reconstruct the failed
disk. Since the disk is mirrored, it does not matter if one on them fails because both disks
contain the same data at all times. Either disk can act as the operational disk. This level
provides 100% redundancy because each drive in the system is duplicated. This type of
array is used for read-intensive, fault tolerant required configurations. Two or more disks
are required to configure this type of RAID level.