NEC EXP200, Руководство пользователя

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10-4 Internal Cabling Diagrams
Connection of Disk Array Controller N8103-89 (SATA)
If serial ATA (SATA) disk drives 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 RAID0, RAID1, and RAID5.
„
RAID0 (striping)
Stores data on two hard disk drives by dividing it (striping). Both hard disk drives can be
accessed at the same time. This improves disk access performance compared with using a
single hard disk.
IMPORTANT:
„
RAID0 does not have data redundancy. When a hard disk drive
failure occurs, data cannot be restored.
„
Logical capacity of the array becomes a multiple of the connected
hard disk drive.
„
RAID1 (mirroring)
Stores the data being saved to one hard disk dive to another hard disk drive. This method
is called "mirroring." When storing data onto one hard disk drive, the same data is
simultaneously stored onto another hard disk drive. When a hard disk drive becomes
faulty, the one with the same data can be used. This provides operation without the system
going down.
IMPORTANT:
„
RAID1 reads or writes data to/from the two hard disk drives at the
same time. The disk access performance is lower than the single
disk.
„
Logical capacity of the array is equal to one hard disk drive
connected.
„
RAID5 (st parity)
Stores data onto four hard disk drives by dividing it (striping) in the same way as RAID0.
With RAID5, parity (redundant data) is also divided and stored on four hard disk drives.
Even if one of the configured hard disk drives becomes faulty, data can be used without
any problem.
IMPORTANT:
„
Because data is read from or written to four hard disk drives
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 four hard disk drives.