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Re: RAID Controllers

From: Scott Marlowe <scott(dot)marlowe(at)gmail(dot)com>
To: David Boreham <david_list(at)boreham(dot)org>
Cc: pgsql-performance(at)postgresql(dot)org
Subject: Re: RAID Controllers
Date: 2011-08-23 23:01:00
Message-ID: CAOR=d=3Vdm=YR-b5q7gvTvKe-CyrLF4vb2FMpkqWF1L-kcLW5g@mail.gmail.com (view raw or flat)
Thread:
Lists: pgsql-performance
On Tue, Aug 23, 2011 at 4:42 PM, David Boreham <david_list(at)boreham(dot)org> wrote:
> On 8/22/2011 10:55 PM, Scott Marlowe wrote:
>>
>> If you're running linux and thus stuck with the command line on the
>> LSI, I'd recommend anything else.  MegaRAID is the hardest RAID
>> control software to use I've ever seen.  If you can spring for the
>> money, get the Areca 1680:
>> http://www.newegg.com/Product/Product.aspx?Item=N82E16816151023  Be
>> sure and get the battery unit for it.  You can configure it from an
>> external ethernet connector very easily, and the performance is
>> outstandingly good.
>
> Thanks. I took a look at Areca. The fan on the controller board is a big
> warning signal for me (those fans are in my experience the single most
> unreliable component ever used in computers).

I've been using Arecas for years. A dozen or more.  Zero fan failures.
 1 bad card, it came bad.

> Can you say a bit more about the likely problems with the CLI ?

The MegaCLI interface is the single most difficult user interface I've
ever used.  Non-obvious and difficult syntax,  google it.  You'll get
plenty of hits.

> I'm thinking that I configure the card once, and copy the config
> to all the other boxes, so even if it's as obscure as Cisco IOS,

I've dealt with IOS and it's super easy to work with compared to MegaCLI.

> how bad can it be ? Is the concern more with things like a rebuild;
> monitoring for drive failures -- that kind of constant management
> task ?

All of it.  I've used it before just enough to never want to touch it
again.  There's a cheat sheet here:
http://tools.rapidsoft.de/perc/perc-cheat-sheet.html

> How about Adaptec on Linux ? The supercapacitor and NAND
> flash idea looks like a good one, provided the firmware doesn't
> have bugs (true with any write back controller though).

I haven't used the newer cards.  Older ones had a bad rep for
performance but apparently their newer ones can be pretty darned good.

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