Sans Digial TowerSTOR TS25CT
Sans Digital TowerSTOR TS25CT User Manual
9
Parity Protection (RAID 3 and RAID 5)
The XOR engine in the RAID controller generates parity
block. In RAID 3 mode, parity block will be stored in the
same hard disk drive. In RAID 5 mode, parity block will
be spread over all of the different hard drives.
The RAID controller will also make use of the same size
disk space in each hard disk under RAID 3 / RAID 5
condition.
Failure in a hard disk will cause the RAID controller to
enter into degraded mode. Host controller still could
rear/write data thru the RAID normally without knowing
any defects. Users have to replace the defective hard
disk. The RAID controller will then enter into online-auto-
rebuild mode automatically.
1.3.2 RAID Levels Summary
RAID
Level
No. of
Allowed
Failed
Drives
Description
Min. # of
Drives
0 None
Block striping is provided and yields higher
performance than with individual drives. There
is no redundancy.
2
1 (10)
1 (2)
Drives are paired and mirrored. All data is
100% duplicated on an equivalent drive. Fully
redundant. RAID 1 if use 2 drives; RAID 10 if
use 4 drives.
2
LARGE None
Large is similar to RAID 0 in that it
concatenates the capacity of all member drives.
The data is written linearly starting with the
first disk drive. When first disk drive becomes
full, the next disk drive is used. Large can have
2 or more disk drives. There is no data
redundancy.
1
CLONE
No. of
drives
minus 1
Clone provides multiple copies of data in a disk
drive. Clone can have 2 or more disk drives.
2
3 1
Data is striped across several physical drives.
Parity protection is used for data redundancy.
3
5 1
Data is striped across several physical drives.
Parity protection is used for data redundancy.
3
