Dell/LSI RAID controllers

[Peter C. Lai]

On 2009-09-25 10:58:18PM -0400, Charles Sprickman wrote:
> On Thu, 24 Sep 2009, Scott Long wrote:
> 
>> On Sep 23, 2009, at 11:12 PM, Charles Sprickman wrote:
>> 
>>> Hello all,
>>> 
>>> I'm considering a Dell, specifically the Poweredge 2970, and I'm not 
>>> finding much info on their site about the various raid controller options 
>>> - there don't seem to be any actual specs.
>>> 
>>> Anyone here familiar with the various models (PERC 5i, PERC 6I, SAS 6/iR) 
>>> and what FBSD driver each one uses?  All are within my price range.  I 
>>> assume all can handle SATA as well as SAS, correct?  Is performance in 
>>> the ballpark of a $500 3Ware or Areca card?
>>> 
>>> Thanks,
>>> 
>> 
>> Dell hardware works well and is well supported.
> 
> That's good to know.  Before I hit the Dell site, I was looking at 
> barebones Supermicro servers (and some others) and Dell beat the "build it 
> yourself" price by a wide margin.  Currently there's a $460 discount on the 
> 2970.
> 
>> SAS5/6 means that it's a SAS+SATA controller that does basic RAID0 and 
>> RAID1.  PERC5/6 means that it's a full-fledged caching RAID controller. 
>> There is even a management tool for both the SAS5/6 and PERC5/6 
>> controllers.
> 
> Does Dell bother documenting this stuff anywhere?  I find their website 
> barely usable (both in terms of response time - awful and organization - 
> also awful).

You are probably going to have to get used to resorting to mapping Dell's
Linux side of the house to what you know about FreeBSD (as the latter will
never be officially supported, even though you will probably find some 
sympathetic Dell engineers on the mailing lists who do contribute to the 
project).

So I would start at http://linux.dell.com/storage.shtml as well
as getting on the mailing lists.

> 
> Does the SAS6 do mirror+stripe?  Is the management tool something that 
> requires the whole boatload of Linux compat stuff or is it something simple 
> like "mptutil"?

Probably not both at the same time (i.e. RAID1+0/RAID0+1).

> 
> Lastly, I see the PERC6 is about $300 beyond the "integrated" SAS6ir. What 
> more does the PERC version offer?  Google is showing me some people calling 
> the non-PERC "quasi-raid" which worries me...

It's quasi in the Intel Matrix sense.

-- 
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Peter C. Lai                 | Bard College at Simon's Rock
Systems Administrator        | 84 Alford Rd.
Information Technology Svcs. | Gt. Barrington, MA 01230 USA
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