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Direct-Attached MD3860f Array, 60x 8TB drives, and creating a 300 to 400 TB drive in Windows Server 2012 R2
We're extending the storage for a PE 730xd backup server with 24 internal drives by adding an FC-attached MD3860f aray, with 60x 8TB drives.
We've kicked around 10, 12, and 15-disk RAID LUNs (RAID5 or RAID-dual-parity). 5x 12-disk RAID-DP LUNS is our most likely layout. We've tested a RAID-DP disk rebuild, and it took 40 hours, so RAID5 probably isn't going to work.
From multiple LUNS, we want one big drive in Windows. We could do this with a logical drive spanning 5 LUNS/volumes, but Dell PowerVault support folks cautioned us not to do this.
We could look at Windows Storage Spaces, but that doesn't work for FC (or iSCSI) drives.
We could use Dell Dynamic Disk Pools (recommended by Dell support) but these max out at 64 TB per virtual disk, so we would still have to link/stripe/extend these drives together in Windows.
So... how do people do this with MD3 arrays?
Is there another layer of striping, or logical drive creation across LUNs, in the MD3 that we're missing?
Anonymous
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December 4th, 2015 17:00
Hello,
BTW, you posted this in the Equallogic Storage Forum not the one for the MD line.
I personally don't like single huge virtual volumes. Especially with RAID5. A double fault on one RAIDset will take out the entire volume. Since this is a backup server, I'm guessing that it will be backing up multiple servers? Not just a 64TB file? You can get a similar virtual presentation buy using mount points instead. In that configuration a double fault only affects a subset of the total backup. Or if you do require more than 64TB for each backup, then just virtualize those two.
Dell storage for drives larger than 2TB need to be at RAID5-DP (aka RAID6). This is especially true with NL-SAS 7200 RPM drives. As you found out, rebuild times are very long, so risk of double fault is increased.
Regards,
Don
dcsnv
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December 6th, 2015 09:00
Thanks Don.
I don't really want a single large RAID set, I would like multiple RAID5-DP LUNS, combined to form a single logical volume. I'm familiar with mount points, and we may use them, but our backup storage patterns are a little bit difficult to predict.
Can you move this to the right forum? Or should I move it?
Anonymous
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December 6th, 2015 12:00
Hello,
I'm not referring to a single RAIDset, but a single logical volume. I was referring to making up that volume with joined RAID5 RAIDsets. Too much risk of a single faulted RAIDset causing an outage.
I was just trying to highlight the risk, especially with such large drives. You mentioned taking 40 hours to rebuild, but was that with a load or just as a test? If just a test, I would expect it to take longer with an active load. I should have been clearer, Dell's suggested storage policy is that for drives larger than 2TB on 7200 RPM drives RAID6 or RAID10 should be used. My apologies.
I'm not an administrator so I can't move the to the other forum.
Regards,
Don