# PXC WAN Design

**URL:** <https://forums.percona.com/t/pxc-wan-design/5003>\
**Category:** Percona XtraDB Cluster 5.x\
**Created:** [July 27, 2016, 9:57am UTC](https://forums.percona.com/t/pxc-wan-design/5003 "2016-07-27T09:57:55Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![tom\_smith](https://avatars.discourse-cdn.com/v4/letter/t/5fc32e/32.png) [@tom\_smith](https://forums.percona.com/u/tom_smith)\
**Post date:** [July 27, 2016, 9:57am UTC](https://forums.percona.com/t/pxc-wan-design/5003/1 "2016-07-27T09:57:55Z")

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I am attempting a preliminary stab at a PXC design in support of a  
web-based application. A Drupal framework is used to generate over 120  
websites for various units within my client’s organization. The  
organization has two data centers, one on each coast of the U.S. The  
semi-static data for each website resides in a mostly read-only MySQL  
database on a public-facing VM in a DMZ which is firewalled from  
the rest of the organization’s network. Databases are backed up every  
day using mysqldump locally. There is no replication per se, but what  
amounts to duplicates of the VMs are pushed from the primary data center  
to the secondary every day. Unit administrators periodically modify the  
data for their websites.

Increasing numbers of organization units are requesting websites, with  
as many as a dozen going live in a single month, but averaging about one  
per week. The expectation is that eventually over 300 websites, and,  
hence, 300 separate MySQL databases, will be required.  
What is the best way to use PXC to provide both HA and failover for  
this environment? Should I contemplate placing 3 distinct sets of  
databases (A-G/H-O/P-Z, for example) in three separate clusters,  
each of three nodes, at the primary data center? And should I also  
consider expanding the clusters to the other data center instead of  
trying to figure out how to replicate to the secondary site? Or can I  
run straight MySQL replication from a node of each cluster on the  
primary to a slave on complementary clusters at the secondary site?

Any insight would be appreciated.