Re: Is there a performance advantage of adding a second parity set?

[DrFranken <midrange@xxxxxxxxxxxx>]

Rob,

  You are correct, Enabler, Repeater, same gizmo. Two versions 
available: one with dual bus (allows pass through to a second repeater) 
and has two ports (FC #5742) and one with one bus - one port  (FC #5741).

   Not having disk units the can shouldn't make it mad at all. Not sure 
what's up with that. There are rules as to which slots can have a FC 
#5742 and which a FC #5741. If you got that wrong then that could easily 
cause the problem. Also you can cable from FC #5742 through to a FC 
#5741 but you cannot cable one FC #5742 to a second FC #5742.  Part of 
the trick with the FC #5742 is it elevates the SCSI addresses of all the 
disks in the second Can so that they don't conflict with the first. It 
sounds to me like you have an address conflict which would certainly 
make some disks 'disappear'.  Can't hurt to format and initialize on the 
other machine but I don't think it will help.

  I believe the rules are on the card in the system but if not the 
rules are here:

http://publib.boulder.ibm.com/infocenter/powersys/v3r1m5/index.jsp?topic=/iphal_p5/scsidiskdriveenclosureconfigure.htm

   - DrFranken

> It was there, the cable from it to the dual was disconnected due to some
> issues we are having.  I figured out what you call an enabler is what
> others might call a repeater.
>
> I think the error I was getting was due to the fact that I had the
> repeater there, but no disk drives in the can.  I added some disk drives
> to the can and got heck.  It said the rest of the disks in there are now
> missing.  So I disconnected the cable again and ripped out the drives.
> Hoping it was because they were used by us in another machine.  So I am
> running them through "format and initialize" on another machine and will
> try again.
>
>
> Rob Berendt
>