Difference between Raid group and parity group?

[Srinikalyan]

Can anyone explain me the difference between Raid Group and parity group in xp12000?
And what does this mean?
7D+1P -72GB 15KRPM (GB)

Thanks,
Srini

[Greybeard · Accepted solution]

7d+1p is the same as raid5 N+1 meaning that for a raid5 of 8 disks the capacity of one will be used for the parity data so you get the capacity of the remaining 7 as useable space. (raid5 ALWAYS uses the space from one disk in an array of 3 to 'X' disks) don't worry too much about the concepts of the storage if RAID is confusing you, just be aware of the "loss" of capacity versus performance when allocating physical capacity to users. eg. raid1 will use TWO disks for every one seen.

[Kranti Mahmud]

Hi Srini,

RAID groups can contain single or multiple parity groups. You can think of the RAID group as the actual RAID container for data protection, and the parity group as a partition of that container. This way, multiple LUNs can be created from each RAID group, and ported out to the same or different servers. This allows granularity in LUN sizes being obtained from the RAID group.

If each partition (parity group) is assigned to the same server, there should be no contention for the RAID group's disk resources. You can always just use the entire RAID group as a single parity group and create one big LUN.


Rgds-Kranti

[Taifur]

Hi Srini


Array group/ RAID group:
The number of physical disk drives contained in a RAID group . This number depends on the RAID configuration. For example, there can be two or four physical disks in a RAID1 group. There are four physical disks in
a RAID5 group.


Parity group:
A parity group is a mode of disk operation and configuration.It is
synonymous with the term RAID group

>>7D+1P -72GB 15KRPM (GB)
Means, total 8disk with 1 parity , if one fails you will get 7 disk capacity use.

Check below link for details,

http://209.85.229.132/search?q=cache:3ZSeDRHgpq0J:raid5.nl/UserGuide12000.pdf+Raid+Group+and+parity+group+in+xp12000&cd=6&hl=en&ct=clnk&gl=bd#32


http://209.85.229.132/search?q=cache:criU5dPD5wYJ:h71028.www7.hp.com/ERC/downloads/4AA0-7923ENW.pdf+7D%2B1P+-72GB+15KRPM+(GB)+in+xp12000&cd=1&hl=en&ct=clnk&gl=bd

If helps, pls assign point.

Rgds//
Taifur

[IBaltay]

Hi, lets take it this way:
In XP the most common RAID5 array groups are 8 physical disks which can create the parity group of 7D+1P, with the interleaved=striped concatenation of 2 or 4 this kinda array groups, we could create the parity groups of 14D+2P or 28D+4P

[Sivakumar MJ._1]

In XP12k RAID group :
One or two array groups formatted with a common RAID level. RAID1 parity
groups consist of 4 HDDs (2D+2D) or 8 HDDs (4D+4D). RAID5 parity groups
include a parity disk but also consist of 4 HDDs (3D+1P) or 8 HDDs (7D+1P).
All RAID6 array groups are made up of 8 HDDs (6D+2P).

Array group : A group of four identical unformatted disk drives (HDDs) which are
formatted into Parity groups (also called RAID groups).

[Srinikalyan]

Thanks for the answer.