Does Percona MongoDB still use Ark consensus algorithm ?

[brew74]

I have seen the a few blogs about Ark consensus algorithm Percona server adopted.

https://www.percona.com/blog/2014/07/18/introducing-ark-a-consensus-algorithm-for-tokumx-and-mongodb/
https://www.percona.com/blog/2014/07/25/explaining-ark-part-2-how-elections-and-failover-currently-work/

I am wondering that still Percona server for MongoDB use Ark consensus rather than MongoDB original consensus model (Modified Raft).

Is it possible that I can use mixed both MongoDB(Percona server for MongoDB and original MongoDB) in the same replica-set ?

Regards,
Matt.

[david.murphy]

Hi Matt,

No MongoDB upstream has made major improvements there are part of the EOL on TokuMX we decide to only keep the engines and some features like hot backup, LDAP and Audit in Percona Server for MongoDB. As such we are using what community has for any election protocol. This does not mean we could not choose to add optionally a way to change the protocol if it made sense, however, we want to make sure you can easily switch from MongoDB Community and PSMDB. Using Ark would not be good there especially when the main issues Ark solves are solved now.

Regarding the second question as part of the desire to keep thing compatible yes you can I suggest you match version as you should think of PSMDB as MongoDB community + features, not as something the behaves in different ways by default.

Cheers
David Murphy

[brew74]

Great,
Thanks for fast & clear answer.

Regards,
Matt.