On Sat, 24 Apr 1999, Francisco Jose Montilla wrote:
> ----------
> Why would I want a two channel RAID card for RAID one?
>
> By putting each harddrive on a separate channel, you can ensure that even
> if a cable or terminator on one channel were to go bad, the system would
> continue to function.
>
> When hot-swapping a harddrive, the RAID card must temporarily stop the
> SCSI channel the drive is attached to. If the other drive in a RAID one
> array is connected to a different channel, the computer can operate
> completely normally during the hot-swap.
> ------------
>
> I agree completely with the first statement. But the second sounds
> somewhat odd to me. I can hotadd or hotremove a disk on linux with sw RAID
> and a non-hot swappable capable controller, maybe this is another feature
> of sw RAID over hw RAID?
Because you're _supposed_ to quiet the SCSI bus while you'ure swapping your
disk to prevent errors in active requests when you're removing or inserting
a device into the bus.
Just because you can get away with swapping a disk on an active SCSI bus
most of the time (I assert that you're not really getting away with it
_every_ time - you're just unaware of it) doesn't mean it's the right away
to do it...
All of this only applies if there are multiple devices on the bus (of
course).
-Andy
Global Auctions
http://www.globalauctions.com
