Re: Looking for a cheap upgrade (RAID)

On 6 May 2003, Ron Johnson wrote:

> On Tue, 2003-05-06 at 13:12, scott.marlowe wrote:
> > On 6 May 2003, Ron Johnson wrote:
> >
> > > On Mon, 2003-05-05 at 17:22, scott.marlowe wrote:
> > > > On 5 May 2003, Ron Johnson wrote:
> > > >
> > > > > On Mon, 2003-05-05 at 11:31, scott.marlowe wrote:
> > > > > > On 3 May 2003, Ron Johnson wrote:
> > > > > >
> > > > > > > On Fri, 2003-05-02 at 13:53, Chad Thompson wrote:
> > > [snip]
> > > > > What controller do you use for IDE hot-swapping and auto-rebuild?
> > > > > 3Ware?
> > > >
> > > > Linux, and I don't do hot swapping with IDE, just hot rebuild from a
> > > > spare drive. My servers are running SCSI, by the way, only the
> > > > workstations are running IDE. With the saved cost of a decent RAID
> > > > controller (good SCSI controllers are still well over $500 most the time)
> > > > I can afford enough hot spares to never have to worry about changing one
> > > > out during the day.
> > >
> > > Ah, I guess that drives go out infrequently enough that shutting
> > > it down at night for a swap-out isn't all that onerous...
> > >
> > > What controller model do you use?
> >
> > My preference is SymBIOS (LSI now) plain UW SCSI 160, but at work we use
> > adaptec built in UW SCSI 160 on INTEL dual CPU motherboards. I've used
> > RAID controllers in the past, but now I genuinely prefer linux's built in
> > kernel level raid to most controllers, and the load on the server is <2%
> > of one of the two CPUs, so it doesn't really slow anything else down. The
> > performance is quite good, I can read raw at about 48 Megs a second from a
> > pair of 10kRPM UWSCSI drives in a RAID1. These drives, individually can
> > pump out about 25 megs a second individually.
>
> Hmm, I'm confused (again)...
>
> I thought you liked IDE RAID, because of the price savings.

No, I was saying that software RAID is what I like. IDE or SCSI. I just
use SCSI because it's on a server that happens to have come with some nice
UW SCSI Drives. The discussion about the IDE RAID was about what
someone else was using. I was just defending the use of it, as it is
still a great value for RAID arrays, and let's face it, the slowest IDE
RAID you can build with new parts is probably still faster than the
fastest SCSI RAID arrays from less than a decade ago. Now with Serial ATA
coming out, I expect a lot more servers to use it, and it looks like the
drives made for serial ATA will come in server class versions (tested for
longer life, greater heat resistance, etc...)

On my little 2xPPro200 I have 6 2 gig UltraWide 80 MB/sec SCSI drives, and
2 80 gig DMA-33 drives, and the two 80 gig DMA-33 drives literally stomp
the 6 2 gigs into the ground, no matter how I configure it, except at
heavy parallel access (i.e. pgbench -c 20 -t 1000) where the extra
spindle/head count makes a big difference. And even then, the SCSIs are
only a tiny bit faster, say 10% or so.