Explaining Raid Devices In The Raid Setup Report; Raid Setup Report - HP StorageWorks P4000 User Manual

RAID level
RAID 1+0 –
Mirroring and
Striping
RAID 5
RAID 6

Explaining RAID devices in the RAID setup report

In the Storage category, the RAID Setup tab lists the RAID devices in the storage system and provides
information about them. An example of the RAID setup report is shown in
in the report is described in
Figure 10 RAID setup report
.
Description
Offers the best combination of data protection and performance. RAID 1+0 or drive mirroring
creates fault tolerance by storing duplicate sets of data on a minimum off our hard drives.
There must be an even number of drives for RAID 1+0. RAID 1+0(10) and RAID 1 are the
most costly fault tolerance methods because they require 50 percent of the drive capacity
to store the redundant data. RAID 1+0(10) first mirrors each drive in the array to another,
and then stripes the data across the mirrored pair. If a physical drive fails, the mirror drive
provides a backup copy of the files and normal system operations are not interrupted. RAID
1+0(10) can withstand multiple simultaneous drive failures, as long as the failed drives are
not mirrored to each other.
Offers the best combination of data protection and usable capacity while also improving
performance over RAID 6. RAID 5 stores parity data across all the physical drives in the
array and allows more simultaneous read operations and higher performance. If a drive
fails, the controller uses the parity data and the data on the remaining drives to reconstruct
data from the failed drive. The system continues operating with a slightly reduced perform-
ance until you replace the failed drive. RAID 5 can only withstand the loss of one drive
without total array failure. It requires an array with a minimum of three physical drives.
Usable capacity is N-1 where N is the number of physical drives in the logical array.
Offers the best data protection and is an extension of RAID 5. RAID 6 uses multiple parity
sets to store data and can therefore tolerate up to 2 drive failures simultaneously. RAID 6
requires a minimum of 4 drives. Performance is lower than RAID 5 due to parity data up-
dating on multiple drives. RAID 6 uses two disk for parity; its fault tolerance allows two
disks to fail simultaneously. Usable capacity is N-2 where N is the number of physical drives
in the logical array.
Table 11.
Figure 10. Information listed
P4000 SAN Solution user guide 55