Can Adaptec AIC-7902 do RAID-5?

[Scott Long]

Sheldon Hearn wrote:
> Hi folks,
> 
> I've been googling like crazy and have gotten mixed answers on the
> AIC-7902's RAID support.
> 
> The product spec says it can do RAID-0 and RAID-1.  Other articles show
> benchmarks involving RAID-5.  I'm concerned that this is software
> RAID-5, which won't do me any good at all for FreeBSD.
> 
> Any FreeBSD users using an AIC-7902 with 3 or more disks in a RAID-5
> configuration?
> 
> Thanks,
> Sheldon.

A 7902 by itself is _just_ a scsi chip.  Any RAID functionality comes
either from software drivers or extra hardware[1].  Adaptec has two
product lines involving the 7902 chip and RAID.  The 'HostRAID' line
is just a standard 7902 combined with software RAID drivers for levels
0, 1, and 10, and a BIOS that supports booting off of these levels.
The 2200S and 2120S cards are hardware RAID and can do 0, 1, 5, 10, and
50.

Scott

[1] The marketing literature for the 7902 will say that it contains
features that accelerate RAID 1.  This still means that it has to have
a software driver doing the rest of the work.