NEC Express5800/110Ei, Руководство пользователя

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10-4 Internal Cabling Diagrams
Connection of Disk Array Controller (SATA)
If serial ATA (SATA) disks are installed, the disk array controller (SATA) can be connected to the
server. The disk array controller (SATA) is an optional PCI RAID board provided to improve the
data reliability. It supports RAID5 as well as the RAID levels supported by the disk mirroring
controller (RAID0 and RAID1).
„
RAID0 (striping)
RAID0 provides block "striping" across multiple drives, yielding higher performance than
is possible with individual drives. This level does not provide any redundancy.
IMPORTANT:
„
If either of the two hard disks configuring the array is defected, the
data cannot be recovered.
„
The logical capacity of the array is an integer multiple of the
capacity of a connected hard disk.
„
RAID1 (mirroring)
The hard disk drives are paired and mirrored. All data is 100 percent duplicated on a drive
of equivalent size.
IMPORTANT:
„
Because data is read to or written from two hard disks concurrently,
the disk access performance is lower than that of the configuration
using only a single disk.
„
The logical capacity of the array is the same as the capacity of a
single connected hard disk.
„
RAID5 (st parity)
Data is "striped" across three physical disk drives. For data redundancy, drives are
encoded with rotated XOR redundancy.
IMPORTANT:
„
Because data is read from or written to three hard disks concurrently,
the disk access performance is lower than that of the configuration
using only a single disk.
„
Because the parity data is saved, the logical capacity is a little lower
than the total capacity of the three hard disks.