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Expanding P2000 G3 SAS storage with D2600 shelves

Hello, I have a Dual-controller P2000 directly attached via SAS 6Gb to four ESXi hosts

The P2000 currently has 12x 600GB SAS 15K LFF disks in RAID10, 1 vdisk

We are looking to add around 12TB of usable capacity to it, on RAID10

I wanted to ask if it's better to get:

1x D2600 LFF shelf with 12x 2TB LFF 7.2k rpm SAS disks (3.5-inch SC Midline, 652757-B21 )

or 2x D2600 shelves with 12x 1TB LFF 7.2 rpm SAS disks each? (3.5-inch SC Midline, 652753-B21)

Usually we carve 600-700GB LUNs and present them to our ESXi 5.1u1 hosts

Is there a chance we might hit I/O bottleneck by adding 2 shelves? if I understand correctly the  max throughput with the 6Gb SAS interface is 750MByte/sec ? 80% of the storage will be consumed by the 2 hosts.

Are HP 7.2k rpm drives recommended for this SAN or is the performance severely impacted when compared to the regular 600-900GB 15k rpm?

The other option for us would be the SFF version of the enclosure with 24x 900GB 15k rpm SAS SFF disks, which would be about 3x the price. Are these 900GB 15k disks going to give us 3x the performance? I'd like to keep the cost of this upgrade around $8-10k

Thank you
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Zephyr ICT
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2 shelves full of 1TB disks will be twice as fast as 1 shelf of 2TB ones, that's pretty obvious. You can use the simple calculator at http://www.eprich.com/tools/simple-raid-group-calculator . The random IOPS figures are fairly accurate although may be a bit high for 7.2K drives and a bit low for 15K ones.

You have to be aware that SATA disks are not natively dual-ported, the 3.5" MSA disks have an interposer to make them dual-ported but the 2.5" ones do not so SFF SATA are only useful on a single controller model with no failover.

The SAS 6Gb cables/connectors have 4 lanes and these are grouped into a wide port so it's really 24Gb, not that you can achieve anywhere near that with the type or random I/O you'll be throwing at it.

652757-B21 are SC drives, the disks are the same as other SFF ones but they are in HP's new style gen8 caddies and won't fit in the D2700, 619291-B21 is the 900GB SFF disk in the correct caddy. There's also a different part number for exactly the same thing marketed by the Storageworks division rather than the server division but the Quickspecs have been updated to say "HP MSA P2000 G3 Arrays support both the HP ProLiant Server SFF Hard Disk Drives and HP MSA SFF Hard Disk Drives" so you can now use whichever is cheapest.
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Thank you, we will go with two additional enclosures (each enclosure with 12x 600GB SAS 15k RPM, 3.5" in raid10), and if the usable storage is not enough we will add a third enclosure with 3TB SATA 3.5".

I though that the D2600/2700 were the only options for adding disks, but I see now the below part at the quickspecs:

HP P2000 Modular Smart Array 3.5-in Drive Bay Chassis (LFF)      AP838B

Is this in any way inferior to the D2600/D2700?

Pricing is better with this, so I can get two of them, for a total of 7200 GB usable in RAID10, we will carve 12 * 600GB LUNs and present them to four SAS-attached DL380 hosts

I see that there is a limit of 16 drives per RAID10 vdisk, so we will likely do 2 vdisks of 12 drives each.
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Thanks for the advice! any further ideas about planning this expansion appreciated.
>I though that the D2600/2700 were the only options for adding disks, but I see now the below part at the quickspecs:

One of those isn't even an option nor has it ever been. You'll have to give me some poinks next time to find out why though.
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Thanks andyalder -- the AP838B should be good though for expanding the P2000 G3 SAS?

PS. I saw the D2600 is not supported for shared storage in your other answer :)

posting it here for anyone else interested:
https://www.experts-exchange.com/questions/27838838/HP-D2600-Keeps-Crashing-When-Connected-To-Two-Hosts.html
If you want LFF disks then AP838B is the thing to use as an expansion shelf on the P2000 G3. The difference between that and the D2600 is simply the mechanical engineering - the disk caddies are a different shape. The P2000 and all the other MSA2000s are built by Dot Hill and re-marketed by HP under OEM agreement.