Subject: Re: AIC-7899 & RAIDFrame SCSI problems in 1.5.2
To: Colin Surprenant <firstname.lastname@example.org>
From: Greg A. Woods <email@example.com>
Date: 03/12/2002 13:07:28
[ On Tuesday, March 12, 2002 at 10:08:59 (-0500), Colin Surprenant wrote: ]
> Subject: Re: AIC-7899 & RAIDFrame SCSI problems in 1.5.2
> [ On Thursday, February 28, 2002 16:05 Greg A. Woods wrote: ]
> > I had understood the 1.5.2 ahc driver would work well enough with the
> > AIC-7899, only with degraded performance (at least with U-160 drives).
> > Your report suggests this is not correct and that even in 1.5.2 the
> > AIC-7899 support is not good enough for production use with multiple
> > U-160 targets even in degraded mode.
> The AIC-7899 driver I am using is the 1.5.2 with the attach code fix backported
> from current and provided by Johnny Lam in the netbsd-help list. The driver
> actually works "well" in my server and I haven't seen any particular problem
> in the last few weeks of operation (running MySQL and Apache in very light
> load). The problem I reported happened only when I pulled one of the drive
> from its hot-pluggable bay (both drives in RAID1 with RAIDFrame).
You don't say anything about what drives you're using, and I don't
remember if you reported it last time or not. I'm assuming the problems
with the -current ahc driver only affects it when true Ultra-160 (LVD)
drives are attached. With 1.5.2 you won't even be getting more than
80MB/s (40MHz@16bit) attachments regardless of the drive.
BTW, what do you mean by a a "hot-pluggable bay"? SCA drives and
connectors? True SCSI switch on the back of the bay? Compaq bays with
the electrical equivalent of SCA? Some other electrical equivalent of
> Do we know if the FreeBSD version of the ahc driver would better
> interact with RAIDFrame? Or is it not an interaction problem but simply
> a driver flaw when handling drives disconnection?
I don't know that there's any specific "interaction" that's unique to
the new ahc driver -- the existing driver in -current is a now ancient
port of the FreeBSD driver. It works very well with AIC-7880 chips (I
have a Adaptec 2944 card (with onboard AIC-7880) with seven FAST/WIDE
differential drives on it at 20MB/s, and another AIC-7880 chip on the
motherboard with four Ultra-FAST/WIDE SE drives at 40MB/s (and a CD-ROM
that's almost never used)). I have a RAID-5 set on the differential
drives (with a true hot spare), and it works very well with the AHC
driver in -current (at least as of 1.5W).
The FreeBSD-4.0 driver works very well with AIC-7880 _and_ AIC-7899
chips and all kinds of drives I've tried with it, or heard about working
with it. Re-porting the current FreeBSD ahc driver seems long overdue,
but it's something I cannot do, at least not without a great deal of
help from the last person to do the port (and finding the time to do the
Greg A. Woods
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