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