Different

[Postmaster]

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Roy Alexander wrote:

>Is it possible and safe to manage one SSA with two different versions
>of Volume Manager?
>
>Here is my current setup:
>
>   host_a
> -------------
> | OS 2.4    |
> |           |-------
> | VM 2.1.1  |      |    -------------
> -------------      |----| SSA 102   |
>   host_b                |           |
> -------------      |----| FW 3.9    |
> | OS 2.4    |      |    -------------
> |           |-------
> | VM 2.1.1  |
> -------------
>
>One host is active and the other is a hot standby. Only one
>host "owns" the SSA at a time by import/deport of the single
>disk group on the SSA.
>
>We are moving to a more fault tolerant setup with two new
>SSAs and each host connected to both SSAs. Since this system
>is online 24x7, we must upgrade each host separately. As a
>first step, we plan to move to this setup:
>
>   host_a
> -------------           -------------
> | OS 2.4    |           | SSA 102   |
> |           |-----------|           |
> | VM 2.1.1  |           | FW 3.9    |
> -------------           -------------
>
>   host_b
> -------------           -------------
> | OS 2.5.1  |-----------| SSA 112   |
> |           |           |           |
> | VM 2.3    |----       | FW 3.11   |
> -------------   |       -------------
>                 |
>                 |       -------------
>                 |       | SSA 112   |
>                 |-------|           |
>                         | FW 3.11   |
>                         -------------
>
>The real question is could host_b with the newer OS and VM
>manage the old SSA 102 if some unforeseen problem arose with
>the new SSA 112s AND host_a died (failover to host_b)?
>
>If so, what would be required for host_b to "forget" the two SSA
>112s and "learn" about the SSA 102?
>
>We will run in this mixed configuration for a couple of days until
>we are sure there are no problems with the new SSAs, OS, and VxVM.
>During this evaluation period, I wanted to understand what my options
>were for this double fail scenario.
>
>TIA,
>
>Roy Alexander
>
>________________________________________________________________________
> Roy Alexander |  "If you're going to write bad code,
> roya@iex.com  |   do it in someone else's language!"
> IEX Corp.     |   Bjarne Stroustrup -- creator of C++
Roy,

          That is a very big NO!   That is a very big NO!   That is a
very big NO!

I repeat again

          That is a very big NO!   That is a very big NO!   That is a
very big NO!


Unix/VMS System Admin

"If only I had known..."