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I'm planning some expansion on an HP MSA1000 SAN. My boss says that we need to have two separate arrays on the new enclosure, one for Bays 1-7, the other for Bays 8-14. Is there any reason that we need to do this?

My plan was to have the entire expansion shelf be 1 array, then create RAID 6 logical drives from that. I don't understand what splitting drives into separate arrays gain us. We don't have dual controllers, so there's no benefit there.

Thanks, CC

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up vote 4 down vote accepted

MSA1000's are pretty old and are unfortunately limited to creating only 2TB virtual-disks/LUNs - so depending on what size of disks you're using then you could easily have to build more than one virtual disk.

i.e. if you're using 300GB disks then 7 x 300 = ~2.1TB, you couldn't add an eighth drive to it, not in a usable way anyway - so having two blocks of this would mean you'd get at 2+2 TB - is that clear?

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+1. 2TB is your limit. Our [partially] retired MSA has one shelf of 14 x 146GB configured as a single 1.6TB array. The second shelf is 14 x 300GB configured as one 1.6TB array and one 1.7TB array. – jscott May 19 '10 at 16:50
To be honest they're hateful things really, iirc the LUN limit is seriously low (32?) - we have ours to our dev team to mess with :) – Chopper3 May 19 '10 at 16:56
That's clear. I was thinking I could just have one array with 3 logical drives on it. Looks like I'll need to split into 2 arrays, one with 2 LUNs, one with one. Hopefully that gets us through another year. – CC. May 19 '10 at 19:42
That's what you can do with a more modern san box yes, just not that one sorry. – Chopper3 May 19 '10 at 21:24

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