SUMMARY: point-in-time bitmap copy

Date: Fri Apr 20 2007 - 15:09:17 EDT
Sorry about the delay, but Ibve been working this.

Original question:
Running StorEdge Availability Suite 3.2 Point-In-Time copy. All works as
advertised. However when using the deport, import and join functions the
documentation says to simply copy the bitmap to a second bitmap for use on
secondary system. The admin/ops guide says to use 'cp' but the bitmap is not
file system, it is a raw device, so 'cp' probably isn't the correct command.
The Point-In-Time Oracle guide says to use 'dd', but I wonder about the
consistency of the second bitmap if I/O is still being written to the master,
which implies the bitmap is changing. I did find the 'iicpbmp' command which
seems to be a solution, but again the worry about the consistency. (I've
looked at using and not using the '-c' option, but run into possibly
suspending II.) Does anyone know which is the best solution for creating the
second bitmap?

I only got one suggestion to use mirroring to create the bitmaps, but with
over 500 master volumes, that would be problematic. After more reading,
bugging Sun and some experimentation I found an answer. The trick is to not
worry about the second bitmaps as they only come into play when the shadow
volumes are moved to the second system. Once there they record changes to the
shadows. When the shadows are brought back the primary and secondary bitmaps
are used in the join. Basically the steps are:

- When creating the shadow volumes and primary bitmaps also create a second
set of bitmaps in the shadow disk group or some group that can be exported.
- After the enable/updates export the shadows (iiadm bg <ii group> bE)
- Move disk group(s) to second system. (If you donbt know how this is done
you donbt need to be messing with Instant Image.)
- Import each shadow (iiadm bI <shadow volume> <second bitmaps>)
- Set up an II group (iiadm bg <ii group> -m <all shadow volumes>) (This is
optional, but II groups make management much easier.)
- Do what ever to the shadows you want (bring up DB, create/delete/modify
files. etc.)
- Once done unmount and disable the shadows (iiadm bg <ii group> -d)
- Move disk group(s) back to the master system.
- Join the shadows to the master (iiadm bJ <shadow volume> <second
bitmap>)(You can mount the shadows at this point.)
- Update shadows (iiadm bg <ii group> -u s) or masters (iiadm bg <ii
group> -u m)

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Received on Fri Apr 20 15:09:33 2007

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