Opinions: root mirror recovery

[Steve Bulmer]

As a practice, we take a prtvtoc of the system disks before we encapsulate so you can get the low level partition table in the event
of an emergency.

Be aware of a couple things, primarily you can only get to the raw partititions on the encapsulated disk. We've seen sites where the
"primary" (encapsulated) boot drive fails and is replaced and synched to the remaining mirror. Once this is done, there is no going
back to the original partitions for DR or even a Solaris upgrade. At this point, be sure to have good ufsdumps of the OS as you will
need them.

The other thing is that if you are looking at Disksuite, it really does keep everything in the pre-determined partitions making
recovery easier. Using DS to mirror your boot drives means you will need at least another disk for the VXVM/SEVM rootdg (or at least
a partitition).

As someone else mentioned, there is no golden rule. I have even seen sites which "dd" there OS disk to another hard drive for safe
keeping.

Steve

Robert.Cross@scottish-newcastle.co.uk wrote:

> Small question for all the experts out there.
>
> We have an E4000 here with an attached SSA114, running Volume Manager 2.6. Now,
> for
> resiliancy/performance reasons I've encapsulated and mirrored the root volume,
> one copy
> on a SCSI disk tray, and another on the SSA itself.
>
> Talking to one of our Disaster Recovery suppliers yesterday, and he was saying
> that he's been told
> that if the root volume gets trashed, it's very difficult to recover the system
> if the root volume is under
> VM control. He's further been told that it's actually better to install
> DiskSuite from the Solaris 2.6 CD,
> and use THAT to mirror the root volume.  The problem with VM is that apparently
> to recover rootvol
> you need to know what the low level organisation of the disk is. This
> information was given to him
> by a lecturer on a Sun Volume Manager course he attended recently.
>
> Has anyone out there got any experience or opinions one way or another on this?
>
> Thanks
>
> Robert Cross, Systems Programmer, Scottish & Newcastle plc.
>
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