[CentOS] software raid

[Joshua Baker-LePain]

On Thu, 29 Mar 2007 at 3:50pm, Les Mikesell wrote

> Joshua Baker-LePain wrote:
>
>>> The large SAN vendors usually don't recommend building raid5 sets larger 
>>> than 6-8 disks, and will stripe or concatenate multiple of those on the 
>>> typical SAN with 100s of spindles.    Myself, I'll stick with RAID10 for 
>>> anything critical.
>> 
>> Would that I had the money to and still get the space I need.  Even doing 2 
>> 12 disk RAID6 sets (each with a hot spare) gets you 9TB which is 50% more 
>> space for the same money as RAID10.
>
> You are omitting the cost of the raid controller here. For your 12+ ports you 
> don't have much other choice except a dedicated network device.  For the size

What do you mean by a dedicated network device -- do you mean a NAS?  Not 
true.  See, e.g., 
<http://www.siliconmechanics.com/i10219/amd-storage-server.php>.

> that normal people need - or that you might use on other machines, you might

Are you implying I'm not normal?  ;)

> have the option of running raid10 (or 0 + LVM) in software on the motherboard 
> ports plus some dumb $20/port cards and buying several extra drives.

On that note, what cheap add-in SATA controllers have folks had good luck 
with?  I haven't tried *too* hard, but the couple I've tried were far less 
than stable.

There is one advantage of hardware RAID that hasn't been mentioned yet, 
and that's hot-swap.  Last time I tried, software RAID fell over when a 
HDD suddenly disappeared.

-- 
Joshua Baker-LePain
Department of Biomedical Engineering
Duke University