# How to best manage persistent connections **URL:** \ **Category:** Percona XtraDB Cluster 5.x\ **Created:** [February 28, 2025, 10:51am UTC](https://forums.percona.com/t/how-to-best-manage-persistent-connections/36981 "2025-02-28T10:51:49Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![robtigger](https://avatars.discourse-cdn.com/v4/letter/r/74df32/32.png) [@robtigger](https://forums.percona.com/u/robtigger)\ **Post date:** [February 28, 2025, 10:51am UTC](https://forums.percona.com/t/how-to-best-manage-persistent-connections/36981/1 "2025-02-28T10:51:49Z")
I’m seeking the recommended advice on how to best handle the following scenario. The setup is a cluster of 6 MySQL nodes (XtraDB Cluster 5.7.29-32). If one or more of the nodes drop from the cluster and go into a not ready status (wsrep\_ready) any persistent connections remain connected, returning out-of-sync data on reads for a period until the node or nodes rejoin. Does Percona XtraDB Cluster 5.7 offer a way to either drop persistent connections on not ready (wsrep\_ready) nodes? or an option to return an error on reading out-of-sync data? or use the wsrep\_sync\_wait (7) variable? Any help or advice would be greatly appreciated. ---
**Author:** ![matthewb](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/matthewb/32/34_2.png) [@matthewb](https://forums.percona.com/u/matthewb)\ **Post date:** [February 28, 2025, 6:30pm UTC](https://forums.percona.com/t/how-to-best-manage-persistent-connections/36981/2 "2025-02-28T18:30:43Z")
> [@robtigger](#): > > The setup is a cluster of 6 MySQL nodes (XtraDB Cluster 5.7.29-32) Running 6 nodes is not a good idea. You can easily get into 50/50 split brain. Run either 5 nodes, or 7 nodes. Also, 5.7 is dead, dead, dead. Please upgrade to 8.0 as soon as you can. > [@robtigger](#): > > any persistent connections remain connected How does your application connect to PXC? Using a proxy, or direct connections? > wsrep\_dirty\_reads=OFF > When a node loses its connection to the [Primary Component](https://galeracluster.com/library/documentation/glossary.html#term-primary-component), it enters a non-operational state. Given that it can’t keep its data current while in this state, it rejects all queries with an `ERROR: Unknown command` message. The behavior you desire is already enabled by default. Do you have this parameter enabled by accident? ---
**Author:** ![robtigger](https://avatars.discourse-cdn.com/v4/letter/r/74df32/32.png) [@robtigger](https://forums.percona.com/u/robtigger)\ **Post date:** [February 28, 2025, 9:16pm UTC](https://forums.percona.com/t/how-to-best-manage-persistent-connections/36981/3 "2025-02-28T21:16:28Z")
I agree on the split brain and the old 5.7 version; the cluster is soon to be upgraded to 8.0 using odd hosts. I hope this will resolve this issue. Checking the wsrep\_dirty\_reads variable is set to OFF for all hosts. Connectivity is direct to the hosts through a VIP with load balancing (round-robin, monitoring port (ready)). ---
**Author:** ![matthewb](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/matthewb/32/34_2.png) [@matthewb](https://forums.percona.com/u/matthewb)\ **Post date:** [March 1, 2025, 1:00am UTC](https://forums.percona.com/t/how-to-best-manage-persistent-connections/36981/4 "2025-03-01T01:00:23Z")
If `wsrep_dirty_reads` is OFF, then you shouldn’t be able to execute any DML/DDL, per what the manual says. In any case, it is the application’s responsibility to observe, and catch error messages, and disconnect from a host if desired. I recommend 2 options: 1) reconfigure your load-balancer check script to monitor `wsrep_primary_component` and return false if not in PRIMARY state. This should cause your load balancer to stop sending connections to that node. OR 2) switching away from VIP/load-balancer to [ProxySQL](https://github.com/sysown/proxysql) which has native support for PXC, and monitors every node state. If a node goes offline, ProxySQL will move frontend connections to active nodes.