Compaq External RAID Controller & Subsystem Infortrend Operation Manual page 43

Table 2 - 1
8. Any spare drives?
9. Limitations?
2-4
RAID Levels
RAID Level Description
NRAID Non-RAID
RAID 0 Disk Striping
RAID 1 (0+1) Mirroring Plus Striping (if N>1)
RAID 3 Striping with Parity on
dedicated disk
RAID 5 Striping with interspersed
parity
Logical Striping one or more logical
Volume drives of different RAID levels
RAID Level Performance Sequential
NRAID Drive
RAID 0 R: Highest
W: Highest
RAID 1 (0+1) R: High
W: Medium
RAID 3 R: High
W: Medium
RAID 5 R: High
W: Medium
Logical Volume Depends on its members;
see above
(Swap Drive Rebuild / Spare Drive Rebuild)
Spare drives allow for the unattended rebuilding of a failed
drive, heightening the degree of fault tolerance. If there is no
spare drive, data rebuild has to be manually initiated by
replacing a failed drive with a healthy one.
As is often ignored, a spare drive (whether dedicated or global)
must have a capacity no smaller than the members of a logical
drive.
Firmware 3.31 and above support 64-bit LBA. A maximum of
64TB capacity can be included in single logical drive.
Up to 128 members can be included in each logical drive.
Extreme array sizes can cause operational problems with
system backup and should be avoided.
Capacity Data Availability
N N/A
N ==NRAID
N/2 >>NRAID
==RAID 5
N-1 >>NRAID
==RAID 5
N-1 >>NRAID
==RAID 5
* Higher; depends
on its members
Performance Random
Drive
R: High
W: Highest
R: Medium
W: Low
R: Medium
W: Low
R: High
W: Low
Depends on its members
Infortrend