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Is it safe to have a cluster composed of two servers

  • one running DRBD 8.0
  • one running DRBD 8.3 or 8.4

Currently there is only one DRBD server with the 8.0 data.

Will the new added server on DRBD 8.[34] as secondary immediately recognize the existing data format (8.0) of its counterpart primary and keep sync using 8.0 format?

if not, can the DRBD 8.0 be installed on RHEL 6 and used safely, provided that the 8.0 DRBD package is only available on el5?
(target would be, in this case, to run 8.0 on both servers until an upgrade of the first server to 8.[34] is done, then allowing an upgrade of the 2nd one)

Déjà vu
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1 Answers1

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Figured I'd answer here after running into the same basic situation today. The short answer is that yes, you can with your specific versions.

Documentation for most minor upgrades does include maintaining clusters in briefly disparate versions while transitioning, but advises a full shutdown in major transitions like 8.4->9.0.

A more general solution can be found via the protocol-compatibility information in the changelog. If your two versions share a protocol compatibility (so in this case, both 8.0 and 8.3-8.4 speak 86), they're safe to comingle.

To note, I haven't tried this myself in production.

bradq
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