What is a good choice of sata-ii raid controller for freebsd?

[Erik Trulsson]

On Thu, Feb 08, 2007 at 02:51:58PM -0800, Freddie Cash wrote:
> On Thursday 08 February 2007 02:17 pm, Mike Andrews wrote:
> > Jaime Bozza wrote:
> > > Everyone has their reasons - I liked the RAID 6 feature, plus the OOB
> > > management of Areca, plus my history with 3ware wasn't good. :(
> >
> > For what it's worth, 3Ware's latest PCI-E cards (9650 series) now
> > support RAID 6.  The updated twa driver that supports them hasn't yet
> > been merged into FreeBSD (see kern/106488 which I filed 2 months ago)
> > but you can download either the source or the binary for it from 3Ware
> > that works just fine.  The updated 3dm2 for it did make it into the
> > Ports tree.
> >
> > Driver annoyances aside, my 9650SE is considerably faster than my 9500S
> 
> Not all that surprising, since the 9500-series use PATA-133 chipsets with 
> SATA-PATA bridges, and the 9550+ uses a native 3G SATA chipset.  Even 
> though the 9500s are listed as 1.5G SATA parts, you'll never get better 
> than ATA-133 speeds out of them.

Which is quite irrelevant since there are no SATA-disks which actually can
use more speed than that.  (The fastest SATA-disks currently available --
Western Digital's Raptor series has a maximum transfer rate of just under
90 MB/s.  Most disks are significantly slower than that.)

The 133 MB/s one can get out of ATA-133 is quite enough for that (and not
all that much less than the 150MB/s that normal SATA provides. (Some SATA
devices also provide a 300MB/s transfer speed, but since no disks can keep up
with that it does not make all that much of a difference in practice.))

Just about all reviews that have compared both controllers and disks 
with and without SATA-PATA bridges have come to the conclusion that
those bridges do not cause any measurable drop in performance over their
native-SATA counterparts.

The only real drawback with using SATA-PATA bridges is that you cannot get
support for the optional SATA features like NCQ. (But not all native-SATA
solutions support those features either.)


> 
> We didn't realise that when we ordered our first pair of Escalade 9500S 
> 4-port cards.  Thankfully, just after they arrived and before we put in 
> the mass-order, the 9550SX was released and we've standardised on them.

The 9550SX should be a bit faster than the 9500S and the 9650SE faster
still, but that is for other reasons.  (Faster processor for handling the
parity calculations for RAID-5, faster memory on the card, being able to do
more operations in parallell, etc.)


-- 
<Insert your favourite quote here.>
Erik Trulsson
ertr1013 at student.uu.se