IDS 11 RSS promotion to a primary in DR

[bill....@gmail.com]

We are in the process of considering an IDS 11 upgrade. We'd like a
setup that addresses both High Availability, HA, and disaster
recovery, DR. We currently are on IDS 10 with HDR only. I am in the
process of proposing a business case of having IDS 11 with HDR primary
and secondary at one location, and a remote RSS server for DR. A
total of 3 servers.

I attended a presentation at IIUG by Carlton Doe which outlined this -
in his book that accompanies this, he mentions that an RSS server
cannot be promoted to a primary, only a secondary. What about in the
event of a hurricane, bomb, or any kind of complete data center
failure (ie a real disaster) of both the HDR servers - what would the
process be to get the RSS server to now take over as the primary?

Thanks.

[Madison Pruet]

If both the primary and the HDR secondary are lost, then there is no
issue. You would simply issue "make primary" on the RSS node, and it
would function as a stand-alone server.

The issue is that the RSS node is coordinated with the
primary/hdr-secondary node, but unlike HDR, we do not insist that the
RSS node be coordinated with the checkpoint. Because of that, it is not
always possible to promote the RSS node into a primary with the idea
that the existing HDR secondary can become a secondary to the RSS node.
They could have differing recovery checkpoints.

>
> Thanks.

[Nilesh Ozarkar]

In this total disaster scenario (HDR pair down), you can convert RSS to a standard server.

Secondly, RSS can be made primary if it was made HDR Secondary before. Here is how ... in your HA & DR solution, consider a scenario, when your HDR primary fails, you can promote HDR Sec to new Primary and RSS to new HDR Sec. Then if your new primary also fails, you can convert current HDR Sec (i.e. original RSS) to new Primary.

HTH,
Nilesh.

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