> I'm following this thread with great interest, what hardware
configuration
> would any of you recommend for this type of hot swap and go system - I
> want to be able and have some data redundancy for a couple of web
servers
> I have at the harddrive level - where I could swap out a bad disk and
> still have the server reving - gradually rebuilding the replaced
mirror/or parity
> drive/etc
As long as you have the drives on an SCA backplane and the device you
plug the backplane into (the controller) supports hot-swapping, then
things (theoretically) should go fine. If you're using a decent hardware
RAID card, then things usually do. I've heard a few people talk about
certain situations that aggravate a hardware RAID card into doing odd
things, but in my (limitted) experience with swapping out drives, I
haven't run into that.
One of our machines is a quad Xeon built on a SuperMicro 8050
chassis/motherboard combination, I have nothing but praises to say about
it. The chassis has two SCA backplanes that I've plugged into the RAID
controller, and it works wonderfully. At first, I used an AMI MegaRAID,
but there were problems with the Linux driver, and rather than wait for a
fix, I bought a Mylex controller, and it's been fine ever since. When I
did have the AMI card in there, I hot-swapped a drive a few times, it
always worked like a champ. Disk performance kept running at less than
optimal, but still very respectable speeds during the rebuild - and of
course, the buzzer went off the entire time, which made me less than
popular with the other office denizens. ; )
In another machine without an SCA backplane, the AMI cards were very,
very fussy about having the replaced drive be on exactly the same SCSI
channel and ID as the drive that failed. In the little time I had to
fiddle around with the Mylex cards that replaced the AMI's, it seemed to
be more forgiving about things like that.
As another note about the SuperMicro 8050, in about two years of
service, the *only* problem we've ever had with it was when the AMI
MegaRAID driver was causing havoc. Other than that, it's the most
rock-solid machine I've ever used. Other than when the AMI card was in
there, the only reboots it's ever seen were for upgrades. And not only
can I pull out a drive and have the machine keep chugging, I've pulled out
two of the three power supplies and had it keep on chugging, too. : )
steve
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