RAID controller question...

[Bill Broadley]

> As usual, generalizations lead you astray. If you want to hook 10+
> drives to a machine and are seek limited, UIDE won't do it for you,
> even if your sustained bandwidth is much lower than 20 MB/s. Think
> database. Sure, that means you spend more money.

Promise sells a raid array that takes UIDE drives, although I don't
have a price.  It holds 10 UIDE drives (8 data, 1 parity, 1 spare).

Promise also sells controllers for $50 or so that can handle 4 drives
a piece.  Buying 2 would bring you up to 12 drives, althought finding
enough room in a case for that many drives can be a problem without
an external controller from Promise.

Then again 4 16.8 gb drives for $1720 for 67 gb of disk, or 50 GB of
raid 5 storage isn't bad.

> No one has advocated choosing the wrong hardware for a given
> situation. Yet we've had much heat and and little light in this
> disucssion, and many assumptions that your environment and needs are
> everyone else's.

I've found it rather useful.  To each his own...

> BTW, in reference to Alan Cox's comment a while back, I don't think
> that the Linux md drivers have the right stuff for scsi hotswap. It's
> a matter of both hardware and software. I'd love to be wrong about it.

I've hotswapped unmounted drives (intel astor chassis, 5*SCA bays etc), I 
was under the impression that you could trigger a rescan by doing something 
under /proc.    Anyone have additional info?