Practicality of U2s?

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josh

Active Member
Oct 21, 2013
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So I saw this post in the deals forum.

ULTRASTAR DC SN630 | ServeTheHome Forums

Definitely great pricing for 5 years warranty on enterprise SSDs. Great. I can replace my ceph SSD tier (currently on HUSSL/SMLs) or my ZFS caches (currently on PM953s).

However, they're U2. All my servers are SAS/SATA. I've looked around, there aren't really any drop in replacements I can swap out the drive bays for U2 hot swap (except for that weird R720 kit which loses 4 bays). That means I can only use them in the PCIe slots. Seems like most adapters are 1x U2 per full height PCIe. 2U servers run out of those real quick. Even worse for things like C6220. Only 1 full width PCIe and that goes to the 10GbE.

That leaves the option of getting fresh chassis. Looked around on fleabay, doesn't seem to be any 2011-3 chassis which supports U2. Most of them are 3647.

So are these drives usable in scale without tearing up everything and starting from the ground up?
 
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Rand__

Well-Known Member
Mar 6, 2014
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Short reply - No.
You are limited to 4 backplane slots on most older E5 systems (+ whatever else you cram into pcie with various 3U, 2U or even 1U adapters [m2 style])

There are some 24 port NVME E5 boxes but I think they use PCIE switches to act as port replicator (similar to SAS EL backplanes)

But its totally clear why - a regular nvme drive wants 4 PCIE 3 lanes - thats 96 lanes total. An E5 provides 40 lanes ea, so max 80 on a dual board.
But you need a lot of lanes to get data off the server too (network) and a bunch for other matters (usb,sata,ipmi)...so there is not enough left to really map 1:1 on that gen.
 
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josh

Active Member
Oct 21, 2013
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i386 said:
It dependsⓇ

If you bought yourself into a specific vendor look there for upgrade paths.

I use supermicro stuff at home and swapped the backplane in my supermicro 745 and use 1x u.2 in a hot swap bay :)
For "fixing" a supermicro 216 one would need just the nvme backplane (eg: Supermicro BPN-NVMe3-216N-S4 24-port 2U (SC216/219) NVMe direct-attac) for like $300 new.
Click to expand...
I'd need some sort of HBA to plug those into as well right? There's no way I can get that many PCIe lanes
 
J

josh

Active Member
Oct 21, 2013
615
190
43
Rand__ said:
Short reply - No.
You are limited to 4 backplane slots on most older E5 systems (+ whatever else you cram into pcie with various 3U, 2U or even 1U adapters [m2 style])

There are some 24 port NVME E5 boxes but I think they use PCIE switches to act as port replicator (similar to SAS EL backplanes)

But its totally clear why - a regular nvme drive wants 4 PCIE 3 lanes - thats 96 lanes total. An E5 provides 40 lanes ea, so max 80 on a dual board.
But you need a lot of lanes to get data off the server too (network) and a bunch for other matters (usb,sata,ipmi)...so there is not enough left to really map 1:1 on that gen.
Click to expand...
I don't really intend on maxing out all throughput on the nvmes, they're a temporary upgrade from regular SATA that I can dump into the next gen of cheap cloud hardware when the time comes since they have a 5 year warranty. I don't mind using these drives limited at SATA throughput levels because they cost the same price wise so some sort of switching port is perfect. Although a completely new chassis with this built in is better than hacking together some Frankenstein.
 
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