How do you attach two suns to a single SSA?

[terrido]

Judith,

For the hardware, you'll need the sbus host adapter for the ssa for the second 
system, and a fiber cable, of course.  On the SSA side, if you do not already 
have the ssecond 'FC/OM' module that the fiber plugs into, you'll also need one 
of those.

Once the hardware is in place, then it is not difficult to use the devices.

You are correct in that you cannot use the same disks from both systems, but you 
absolutely can use different disks on different systems.

If you are also using the Volume Manager softwrae, this may become more 
confusing.  You'll need to have a 'rootdg' on both systems, and if they are both 
in the SSA, each system will 'complain' about the other's disks during boots, 
etc.  Otherwise, no issues, and if you use other-than-rootdg-diskgroups for the 
majority of your data disks, you'll add the ability to be able to access thsi 
from either system.

For more details please contact your local Sun office, or the 800 number for 
assistance.

have fun!
-Terrie Douglas

> We have an ultra-2 attached to an SSA 200 series, utilizing only about
> 1/2 of the disks in the array. We'd like to attach a second ultra to the
> array, such that:
> 	* it could use the unused disks on an everyday basis
> 	* in the event of a failure of the first ultra-2 the second system
> 		could import the volumes from the failed system and use
> 		them.
> I understand that we cannot access the same disks from two systems at the
> same time - this is not an issue.
> 
> A sun sales engineer said that we'd have to add a second controller to the
> array, attach the second system to the second controller, attach half
> the disks to the second controller, and thus not be able to import the other
> disks. Do y'all agree with this?
> 
> system1-----------------------|array1-controller1--disjoint_set1
>                               |
> system2-----------------------|array1-controller2--disjoint_set2
> 
>  I thought that we could install a second port on the existing array
> controller, connect the second system to it, and logically access disjoint 
> sets of disks in the array, but with the ability to import the other 
> system's volumes in the event of the failure of that system. 
> 
> system1ctrlr1----------------------|                  
>                                    |array1-controller1
> system2ctrlr2----------------------|                  
>                                                       
> 
> I also had the impression that we could have the following config:
> 
> system1-ctrlr1----------|
> system1-ctrlr2-------|  |
> 		     |  |----------|array1-controller1\
>                      |             |                   \
>                   |--|-------------|                    \ bunch of disks
>                   |  |                                  / in one array
> system2-ctrlr1----|--|--|                              /
> system2-ctrlr2----|  |  |----------|array1-controller2/
>                      |             |
>                      |-------------|
> 
> (if we can't access disks in the array simultaneously from two systems
> thru a single controller) such that the second connection to each controller
> is just a hot-spare connection, to be used only in the event of a failure
> of one or the other system - true???
> 
> TIA for any enlightenment you can provide...
> 
> -- 
> Judith Reed
> jreed@appliedtheory.com
> 
>