# Best Pratices for this scenario

**URL:** <https://forums.percona.com/t/best-pratices-for-this-scenario/3904>\
**Category:** Percona XtraDB Cluster 5.x\
**Created:** [November 24, 2014, 7:47am UTC](https://forums.percona.com/t/best-pratices-for-this-scenario/3904 "2014-11-24T07:47:41Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![ansaro](https://avatars.discourse-cdn.com/v4/letter/a/f4b2a3/32.png) [@ansaro](https://forums.percona.com/u/ansaro)\
**Post date:** [November 24, 2014, 7:47am UTC](https://forums.percona.com/t/best-pratices-for-this-scenario/3904/1 "2014-11-24T07:47:41Z")

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Hi everybody and please forgive my english.

I’ve got a 4 server cluster working on a local network environment, everything works like a charm.

Now I’d like to add a new cluster outter the office (WAN). I can only connect the wan cluster to one of the lan cluster (the port listener). So, how could i do that?

Could i add the wan server to the lan cluster adding only two gcomm urls? (wsrep\_cluster\_address = gcomm://{wan\_ip\_of\_local\_cluster},{wan\_ip\_of\_external\_server} (I don’t think quorum will deal with this)

Could i create a second my.cnf on local\_lan\_server configuring a second cluster with only those 2 nodes? (is there anyway to know if both of them are synched?)

Is there any other way?

I would really apreciate some light with this.

Thanks in advance

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**Author:** ![sergeym](https://avatars.discourse-cdn.com/v4/letter/s/ecccb3/32.png) [@sergeym](https://forums.percona.com/u/sergeym)\
**Post date:** [November 24, 2014, 7:58am UTC](https://forums.percona.com/t/best-pratices-for-this-scenario/3904/2 "2014-11-24T07:58:09Z")

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How many servers do you have in second place?  
As I understand you can look on this scheme: [first cluster] \<----master/slave replication-----\> [second cluster].  
But if you are going to write in both clusters and connection between them is down you will be in trouble.

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**Author:** ![ansaro](https://avatars.discourse-cdn.com/v4/letter/a/f4b2a3/32.png) [@ansaro](https://forums.percona.com/u/ansaro)\
**Post date:** [November 24, 2014, 8:40am UTC](https://forums.percona.com/t/best-pratices-for-this-scenario/3904/3 "2014-11-24T08:40:12Z")

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Thank you for your answer sergeym . There’s only one machine in the second place ( an VPS machine) i will only use it if all my office goes down (changing the DNS A record) to ensure minimal service to the application users until office come back. So, both “systems” will never be accesible from the users simultaneously.

I thought about adding the external machine to the cluster becouse of the “transparent” sync when office came back.

What really scare me in a master → slave replication mode is hot resyncing the LAN cluster with the WAN machine.