Redis sentinel, server priority/score

[Justin Keller]

We are using redis sentinel, and it works, but when we take down the primary server (let's call it redis1) and another server takes over, when redis1 comes back online it does NOT become the primary again. Is there a way to set a server priority (score), like in MongoDB? We'd like a certain server to be the primary as much as possible (it has more resources and closer to the web servers in terms of latency).

[The Baldguy]

Redis Sentinel is not designed in the way you are asking about. Redis masters and slaves should be equal in capability, or you will have to manually issue a failover command to have one be a "mandatory master".

That said, if your data set become large you will likely encounter issues doing that as you will be doing extra replication.

[Jan-Erik Rediger]

Sentinel respects the `slave-priority`:
https://github.com/antirez/redis/blob/unstable/redis.conf#L380-L389

On Thu, Jul 16, 2015 at 09:58:56PM -0700, The Baldguy wrote:
> Redis Sentinel is not designed in the way you are asking about. Redis masters and slaves should be equal in capability, or you will have to manually issue a failover command to have one be a "mandatory master".
>
> That said, if your data set become large you will likely encounter issues doing that as you will be doing extra replication.
>

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[Bill Anderson]

Yes but slave priority won't cause a master to be demoted and a slave promoted in its place.

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[Jan-Erik Rediger]

Ah, indeed. I understood the question wrong.

[CharSyam]

Changing master is very expensive operation. so it,s not a good idea 

2015년 7월 17일 금요일, Jan-Erik Rediger<jan...@fnordig.de>님이 작성한 메시지:

[Justin Keller]

Ok, thanks for the reply.

It seems like sentinel was an afterthought, and honestly not great at managing a HA redis cluster. The first red-flag was that is seems to literally change configuration files (internally), which I've never seen before.

Would using RedisLabs enterprise cluster (https://redislabs.com/redis-enterprise) be a better option then?