[geeks] Serial ATA

[Greg A. Woods]

[ On Friday, August 16, 2002 at 11:58:32 (-0500), Shawn Wallbridge wrote: ]
> Subject: Re: [geeks] Serial ATA
>
> Well the big problem with most Promise 'RAID' controllers is that they 
> are just IDE controllers and the actual RAID is done in the drivers

Well, "Duh."  :-)  That's only a marketing problem, not a technical one.
(unless your boss was fooled into buying one on false pretenses and you
now have the technical challenge of dealing with the consequences :-)

> (and 
> why the support for them is binary only)

I don't know a lot about these cards, or Promise products in general, but
I do know that NetBSD-1.6 (in "Release Candidate" state right now) will
support their Ultra{33,66,100,133}/ATA Bus Master Accelerator models
(PDC20246, PDC20262, PDC20265/PDC20267) plus the Ultra100TX2[v2]/ATA Bus
Master IDE Accelerator (PDC20268), though the latter with the following
caveat:

     The core wdc doesn't support modes higher than Ultra-DMA 5, so the
     Promise Ultra/133 is only used at Ultra/100.

I presume that'll be "fixed in the next release" :-)

If those are the cards you're talking about then NetBSD supports them
with the cross-platform pciide(4) driver.

> The 3Ware cards have worked well for us. Huge ass storage for less money 
> (2TB server for $10k CAN). We have tried SCSI array's (8-73GB Hitatchi 
> 10k drives in a Sun 711 connected to an Adaptec 3210S w. 256MB cache) 
> and the performance was about the same (except 4 out of 8 of the drives 
> died within a week). So we are going back to IDE raid.

That's good to hear!  Thanks for posting your experience!

> 3Ware just released a 12 port IDE RAID card which sounds nice. 

Wowza!

> As for OS support, it's pretty good. While they only support Linux and 
> Windows, their drivers are completely open, so any OS could be supported 
> given the interest (and willing and competent programmers). The 
> management interface is a Linux binary, but almost everyone has Linux 
> binary emulation (ok, well maybe not, but it seems like it). I know the 
> cards work in OpenBSD, so I can't see the rest of the BSD's not 
> supporting it (or at least for long).

NetBSD 1.6 (and 1.5.3) has the "twe" driver from FreeBSD, which claims
support for the "3ware Escalade family of RAID controllers."

> One really nice thing, I just read that you can move from a 6x00 series 
> card to a 7x00 series card without having to rebuild the array. To me 
> that is a big deal because the 6x00 series are not made anymore and they 
> are getting hard to find (and we have 4 that I worry about finding a 
> replacement for if they die).

Indeed that is a big deal -- very impressive.

-- 
								Greg A. Woods

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