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Due to events beyond my control, a Dell R420 server my (non-profit) organization relies on as an applications server was built using a Dell PERC H310 raid controller. This is much too slow for the work the machine is expected to do (especially when writing). We have since bought a new server (for other reasons), and the new one has a nice Dell PERC H710p raid controller in it. It is significantly faster.

I would like to repurpose the Dell R420, and to that end, I'd like to upgrade the raid controller for as low a cost as possible. I see Dell PERC 6i raid controllers available on E-bay for very low prices. I have a few questions:

1) In principle, would a Dell PERC 6i be faster than the Dell PERC H310? My understanding is that the H310 has no write-cache, and that the 6i has some.

2) What would it take to install a PERC 6i in the Dell R420? I see right off the bat that the PERC 6i uses a different kind of connector than the H310 and H710p. Do I just need to change the cable/harness, or are the technologies just fundamentally incompatible?

3) Are there any inexpensive third-party raid controllers that would do the job at least well enough to write at 25 MBps (as opposed to the 1-3 MBps I'm getting with the H310)?

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  • What operating system will you be running on the R420? – JimNim Apr 10 '17 at 20:52
  • It will be Windows Server 2012 R2. – nomen Apr 10 '17 at 22:14
  • If you're willing to accept the risk of data corruption in the event of a power loss without UPS coverage, you could also try enabling caching on the volume sitting on that RAID. It won't be the same performance as PERC caching, but it may help – JimNim Apr 11 '17 at 2:23
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In principle, would a Dell PERC 6i be faster than the Dell PERC H310? My understanding is that the H310 has no write-cache, and that the 6i has some.

In principle, yes a PERC 6i would almost certainly perform faster than an H310 given the fact that it has write caching support.

What would it take to install a PERC 6i in the Dell R420? I see right off the bat that the PERC 6i uses a different kind of connector than the H310 and H710p. Do I just need to change the cable/harness, or are the technologies just fundamentally incompatible?

The cabling connector difference you see is SAS-8484 vs SAS-8087. On the PERC 6, I believe a SAS-8484 (controller side) to SAS-8087 (backplane side) connection is used, or SAS-8484 to four SAS connections (if connecting direct to drives).

I believe that the H310/H710 SAS-8087 connector is also SAS8087 on the backplane side.

The newer cards and drives use 6Gbps SAS links, while the PERC 6 only supports up to 3Gbps. Thankfully all SAS6 hard drives should be able to auto-negotiate down to 3Gbps speeds. If your system has a backplane with hot-swappable drive carriers (as opposed to cables directly connected to drives), then I'm uncertain what behavior to expect from the backplane when connected to a PERC 6.

Are there any inexpensive third-party raid controllers that would do the job at least well enough to write at 25 MBps (as opposed to the 1-3 MBps I'm getting with the H310)?

I wouldn't expect 3rd party cards to function/cooperate in a Dell server unless they're manufactured by LSI. Anything that isn't on the support matrix (which I can't spot at the moment) could be a risk... the risk being that you buy a card, and the server won't use it when the BIOS doesn't "like it". This might even still be a risk with a PERC 6 card in a 12th generation Dell server. The best you can do is give the PERC 6 a shot (or even any cheap "LSI 6Gbps SAS" card that has a battery on board), and eat the return shipping cost + restocking fee if it doesn't work.

I understand the challenges of situations like this with non-profits all too well... Good luck!

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  • Thanks for your help. The information you gave me about the SAS connector types was really helpful, and once I had that I was able (after a bit of effort) to find a Dell part number to replace the cable harness. It looks like a Dell NP390 will replace the harness and connect to the 6i and the drives. – nomen Apr 14 '17 at 17:09
  • Excellent! Be sure to update again on whether you're able to get the whole thing working. – JimNim Apr 14 '17 at 23:02
  • I'm pretty close, but the cable harness doesn't quite work. The biggest problem is that the "power" connector for it doesn't match the original harness's power connector (i.e., the plugs don't fit). It also has the wrong form-factor (it expects 2 drives stacked on each other). That wouldn't be the worst thing in the world, though. – nomen Apr 17 '17 at 22:34

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