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I am considering purchasing an HP D2700 for use with SSDs (Samsung Pro 840's), for use in realtime playback of high resolution images. The D2700 has two I/O modules (which I assume are the actual SAS expanders). However, since the enclosure was designed as a SAS enclosure, the "B" module routes to the second port of the SAS drives.

My question is: can the enclosure be rewired such that the "A" expander goes to drives 1-12, and the "B" expander goes to drives 13-25? I don't need the SAS redundancy since I'll be using SATA SSDs. And as-is, from what I can tell, I'll be limiting myself to a single SAS cable's worth of data (4 x 6Gb/sec), which is insufficient for my needs (I need double that).

Is this possible? Are there SFF-8087 type cables that go from the expanders to the backplane? Or do the expanders/ I/O modules jack straight into the backplane?

ewwhite
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Antoine Durr
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1 Answers1

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No. What you're asking for is not possible with the HP D2600 and D2700 storage enclosures.

The two controllers (I/O modules) are intended for dual-ported SAS drives and to provide two paths to the disks.

You are oversubscribed when you use a shelf like this. The link is a 4-lane 6Gbps SAS connection (24Gbps)...

If you want more bandwidth, you need to couple SAS SSDs or disks to a RAID controller or SAS HBA solution that can leverage MPIO (or MPxIO).

What are your real throughput requirements? 6 Gigabytes/second seems unrealistic. Plus, a single PCIe 2.0 link is going to cap at 4 Gigabytes/second...

What types of servers/HBAs are involved?

Edit - you're doing this on a Mac. The only way to get the bandwidth you require is to go with PCIe-based SSD, possibly striping across devices. Call FusionIO.

ewwhite
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    With a need of 6GB/sec I'm sure the budget for a consultant specializing in storage could be hired. – Jacob Apr 18 '13 at 02:59
  • Yes, I realize I'm oversubscribed! On-paper requirements are 1152 MB/sec per left and right eye, so 2300. Then pad by 50% to deal with OS (OS X in my case) and hiccups to maintain realtime playback, so I'm looking at probably 1800MB/sec x 2. Yes, a single x8 PCIe probably won't do it, so my plan was to use a second SAS RAID card (ATTO R680). This is direct-attach storage. – Antoine Durr Apr 18 '13 at 03:17
  • Can you recommend any storage enclosures that handle two SAS expanders and are good for SSDs? – Antoine Durr Apr 18 '13 at 03:23
  • @AntoineDurr How much space do you need? – ewwhite Apr 18 '13 at 09:07
  • @ewwhite Need around 5TB usable. – Antoine Durr Apr 18 '13 at 17:26
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    The Mac is not the right platform for this. – ewwhite Apr 18 '13 at 17:27