Disk Group expansion - EVA8000

[jmh254]

Hello,

I have a disk group of 86 x 300Gb drives an an EVA8000. I have an additional 42 300Gb drives that I have added to this array and are currently ungrouped. I would like to add them to the existing disk group rather than creating a new one. What is the best way to add them, should I just add them all in one go, or should they be added in groups of eight for optimal RSS?

Does the number of disks been added effect the re-leveling time? I know this is a low priority task but I'm just curious on how long it may take.

Thanks

[AnthonySN]

http://forums11.itrc.hp.com/service/forums/questionanswer.do?threadId=1341956

[McCready]

Although adding disks in groups of 8 might theoretically be good, usually after your EVA has been around for a while you may not have all your RSS groups of size 8 anyhow, especially if you don't have a number divisible by 8.

I would add them all at the same time, which not only allows all your leveling to take place at once (and one task to do), but will also allow the EVA to best correct any RSS groups that might be too small (or more likely) too large. But I've found it useful not to be too concerned over exact RSS size and placement as when disks fail and get replaced the EVA does not always make the optimal decisions. In managing 16 different arrays over 7 years, I've never had an entire shelf fail.

The only exception I make to that is if I have several EVA's that have space for additional disks, but not sure where I need the space as yet, and then I will add disks in multiples of 8 and leave the rest ungrouped for possible relocation later.