dl380 g5 storageworks 60 raid config planning

[zn_1]

We are about to take delivery of a dl380 g5 storageworks 60 with 24 1TB drives. our goal is storage and data protection so I understand raid adg / 6 is the hp recommended option.

I also found this whitepaper which seemed to make a lot of sense in support of raid6

http://www.winsys.com/whitepapers/pdfs/Enterprise_RAID_6_White_Paper.pdf

The server will be used to house an offline backup service, this relies on a lot of disc read when sanity checks are carried out on hundreds of gb of data, write is fairly low priority

what is the recommended amount of discs to use to create the arrays?

4 x 6 disc raid adg arrays
3 x 8 disc raid adg arrays
2 x 12 disc raid adg arrays

we are also considering raid 5 with hotspare but I'm concerned with the rebuild time on a 5tb array.

is it correct that more discs reduces rebuild time due to more discs to grab data from?

is it also correct that more discs in an array give a reduction in response?

[Steven Clementi]

The amount of disks in your arrays really depends upon how comfortable you are with the technology.

Having 4 - 6 disk RAID ADG arrays would mean you lose 8 disks worth of space due to parity.

It also means that the performance of the array would probably not be as good as something with more disks.

"is it correct that more discs reduces rebuild time due to more discs to grab data from?" - I would tend to think that having more disks in an array, would allow for a faster rebuild since the total amount of data on any one particular disk is less vs. a disk in a group with a smaller number of disks.

"is it also correct that more discs in an array give a reduction in response?" - Generally speaking, having more disks in an array increases i/o performance.



Steven