On Fri, Oct 19, 2001 at 07:13:50PM -0700, David wrote:

[a bunch of almost unreadable junk containing lines over 300 characters
 long.  I have reformatted it, but please do not send this kind of annoying
 stuff to the NetBSD lists in the future.]

>       While we're on this subject, does anyone know if there are
> future support plans for the IBM ServeRAID (preferrably the 76H6875)
> and AMI MegaRAID, and I'm sure the Myelx DAC960 is already supported,
> but I would like to see a monitor or management tool available.
> I recently ditched FreeBSD off the machine I was throwing the IBM
> ServeRAID in because they don't have any support for it.  I might
> consider putting the Mylex into the NetBSD system, but as long as
> I can find a management tool for it, such as varmon in Linux, I
> wsa told that I can try to run it in NetBSD with the linux_compat,
> and I already have without luck.

I have no idea about ServeRAID performance.  I do note that IBM bought
Mylex, and I believe that the ServeRAID line has been deprecated in
favor of the newer Mylex adapters.

The deal on the MegaRAID controllers is this:  some of these controllers
are I2O and will work with our "iop" driver, while some are not.  Andy
Doran did some work on a driver for the other MegaRAID controllers, which
I was testing for him, but it had some problems, notably data corruption
if you had a lot of write-back cache.

Interestingly, I have seen reports of similar problems with *AMI's own* 
drivers for Linux and other operating systems (e.g. Solaris/x86).  The
upshot is that I simply do not trust the AMI controllers and won't use
them for anything important.

The I2O ones may be better, but I believe Andy was unable to get the I2O
storage console working with them.  It does work nicely with the Adaptec
and DPT I2O cards.

Mylex made cards that used an old proprietary interface (the "DAC960" 
cards) that's supported by our "mlx" driver, cards that did I2O (and
possibly also the "mlx" interface) (the ExtremeRAID 1164 and AcceleRAID
100, 150, 200, and 250 and possibly the ExtremeRAID 3000) and cards that 
do *not* do I2O but do a newer Mylex-proprietary interface (the AcceleRAID
160, 170, and 352, and ExtremeRAID 2000) that is supported by our "mly"
driver.

I have no experience with the I2O Mylex cards -- I keep trying to get one
on Ebay but the prices are irritatingly high.

I have some experience with the DAC960 cards -- these are old beasts and
their performance is generally limited by the memory bandwidth available
to the onboard CPU.  Don't expect to get more than about 15-20MB/sec 
through one of these, no matter what.

I have some experience with the "mly" cards -- they seem decent but you
may have trouble using one in a machine with more than 3GB of RAM.  Also,
performance under our driver is not great, topping out at about 50MB/sec,
which is maybe half of what the Linux driver can do; I didn't ever manage
to figure out why.

Oh, also the mly firmware is a bit stupid about things like sparing; it
picks the spare drive to use without regard to current bus load.  I
expect there are other things it's dumb about as well that I haven't
noticed yet.

The I2O Mylex cards may work with the I2O storage console; you'd want to
ask Andy about that, though he may not know either.

The "mlx" and "mly" cards have special Linux configuration widgets.  There
is some effort to support those in the drivers but AFAIK it's not really
complete.  If it did get completed (perhaps by you) you could run the
appropriate configuration utilities under Linux.

Personally, given my experiences with the various PCI RAID controllers out
there, I'd probably choose an Adaptec I2O-compatible card (many 3200s are 
now available on eBay for decent prices) or maybe a Mylex 250 or 1100.  I 
would avoid the MegaRAID cards, as well as the "mlx" cards other than the 1100 
for performance and stability reasons, and the "mly" cards just because
you'd have to pay list price to get them and for list price, I'd rather
have an Adaptec.

Thor