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I have metaluns stripped across 6 raid groups of 4+1 (2 DAE's) and I would like to add another DAE. I will create another 3 raid groups on this new DAE and would like the metaluns to be stripped across all 9 raid groups without having to migrate any on the metaluns or create concatenated metas. Is this possible?

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1 Answer 1

Certainly. Create identically sized luns on the new sets, and simply add those to the metalun. The CX will rebuild the metalun creating new stripes accross all the member luns.

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This sounds like a migration task.? This will have performance impact as the "live" luns will be read and written to the same spindles again to be re-stripped.? Also, if I add new LUNs to the meta, am I not increasing the size? –  Alan Nov 20 '09 at 10:52
just spoke to EMC and they "suggest" that I expand the raid groups and that will automatically stripe to the new disks. The only problem is that these disks are SATA and I don't want to do more that 5 disks in RAID5 because of possible rebuild time issues... –  Alan Nov 20 '09 at 12:55
Yes, you are increasing the size of the metalun. Is this not what you're attempting to do? It won't be possible to redistribute the data without a loss of performance during the rebuild. I think, but haven't tested this, that the loss of performance will be minor as parity information does not need to be recalculated. –  Roy Nov 20 '09 at 16:40
The rebuild time is dependant on the size of the s-ata spindles, rather than the number of spindles in the set. The increased risk of going from 5 to the reccomended 7-8 spindles per raid 5 set is marginal. If this worries you, you may want to consider migrating to raid 6. –  Roy Nov 20 '09 at 16:42

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