On Wed, Mar 20, 2002 at 09:00:40AM +0100, Thomas Michael Wanka wrote:
> Hi,
> 
> thank you and Jonathan for the fast response.
> 
> On 19 Mar 2002 at 23:47, Thor Lancelot Simon wrote:
> > older model, the 8700, which has a backplane rated only for Ultra2
> > (80MB/sec) instead of the Ultra160 of the 8720, but has the
> > interesting property that as it has no integrated termination, you can
> > daisy-chain them if you want to.
> 
> the units in question are 160 and can be daisy-chained. I can 
> no longer use my Compaq F1s (SA 2/p does not work in a new 
> board and with the new raid controller with VHD connectors I 
> can only get cables that are too long for UW).
> 
> Does hotswap actually work with this devices? And for the 
> disks, any experiences with the "SEAGATE Cheatah 9.1GB, 10,000 
> RPM, 3.5" Low Profile, Wide Ultra2 80 Pin SCSI Hard Drive 
> (ST39102LC)"? I usually tak IBM drives as they stay very cool, 
> but I have a nice offer for the Cheatas (about USD 30 each).

We have a pair of 8720s in a machine here where they're attached to a
Mylex AccelleRAID 352 controller.  The disks are newer 9GB Cheetahs,
ST39205LC I think.  We originally planned to use older Cheetahs, 39103s,
but if you look at the power consumption and heat dissipation you'll see
that packing a bunch of first- or second-generation 10,000RPM disks into
a tight space like this is probably a very bad idea.

Hot-swap does in fact appear to work.

With Ultra160 disks, I see little reason to daisy-chain multiple 5-disk
enclosures; few controllers can keep up with the transaction rate that
five modern disks can handle, and certainly 160MB/sec is not enough bus
bandwidth for more than five disks.

I *think* the SuperMicro units are U160 and can have the termination
disabled for daisy-chaining.  I don't know why the termination on the
Enlight 8720 can't be turned off.

-- 
 Thor Lancelot Simon	                                      tls@rek.tjls.com
   But as he knew no bad language, he had called him all the names of common
 objects that he could think of, and had screamed: "You lamp!  You towel!  You
 plate!" and so on.              --Sigmund Freud