topic Re: SYNC HA in General Topics

SYNC HA

RemoteUser — Fri, 18 Apr 2025 12:26:22 GMT

Hi all,
Members of a ClusterXL in Load Sharing mode must be synchronized.
Members of a ClusterXL in High Availability mode do not have to be synchronized.Although, if
they are not synchronized, current connections are interrupted during cluster failover

I don't understand what exactly he means by:
Members of a ClusterXL in High Availability mode do not have to be synchronized.

From > R81.20 ClusterXL Administration Guide > pag.83

Re: SYNC HA

G_W_Albrecht — Tue, 22 Apr 2025 07:36:33 GMT

If you do not need that a cluster failover keeps up the current connections, you need no state syncronization - but usually, failover should be smooth and not disturbing any connections or services. On the other hand, load sharing needs state syncronization between the nodes as the load has to be shared. You will need a sync connection between HA cluster members anyway as the standby must learn if the active is no longer working and standby has to turn active.

Re: SYNC HA

the_rock — Fri, 18 Apr 2025 18:46:33 GMT

Hey bro,

Essentially, what @G_W_Albrecht had stated is exactly how it works. So, load sharing needs sync, cause members share the load. In HA, it makes sense to have it, so failover is successful. Otherwise, without sync, existing connection wont survive the failover.

Andy