Question
· Mar 31, 2020

Force a failover on a mirror?

Is there a way to force a failover from the primary mirror member to the backup member without forcing down the primary (which happens with ##class(SYS.Mirror).BecomePrimary())? What I'm trying to simulate is a network isolated condition on the primary.

Discussion (6)1
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Hello Dan,

I am struggling to understand the scenario that you are testing/planning for. Do you have an arbiter? I would read through the mirroring docs which discuss the various options available to you and the various automatic responses that mirroring can take (including some diagrams).

https://cedocs.intersystems.com/latest/csp/docbook/DocBook.UI.Page.cls?KEY=GHA_mirror

https://cedocs.intersystems.com/latest/csp/docbook/DocBook.UI.Page.cls?KEY=GHA_mirror#GHA_mirror_set_autofail_outages

If you want to simulate network isolation, I think you'd need to actually network isolate. If you force the backup to become primary, Caché will try to force down the original primary to prevent split brain.