Global Cluster Option with two single node cluster?
The question is simple, i`m checking the requeriments for this configuration, Cab we configure a global cluster between two single node cluster?
According to the characteristics of the customer platform, the only configuration possible to us is to implement a global cluster that is responsible for monitoring replication groups and fail over applications in case of serious failure in the main site.
I understand that we can configure a single-node cluster but I need help to consider any request or cons if we set a global cluster with two single node cluster
Thanks in advance,
I am guessing you mean you
I am guessing you mean you need "Automated" failover rather than automatic failover. What I mean is that you should set Global service groups to have Manual failover and if node dies, then you will get an alert to failover. On accepting the alert, VCS will "automate" the failover. I would not recommend setting Global service groups to have Auto failover as if at the time of failover you are in async mode (which you could be in even with soft sync), VCS will take over even if VVR is behind. Also any network issues between the 2 sites could cause split-brain. With an RTO of 4 hours, automatic failover should not be required.
Whether to go async or soft sync is down to:
- Bandwidth - you can use vradvisor to see if your application ever exceeds 1Mbps - this is small, so I am guessing it might
- Latency - it can be quite hard to guage to tell what the effect the latency will have on your application, so you can just test soft sync and see how your application handles this - you can switch between async and soft sync on the fly, so it is not a "hard" setting
If your RPO is 1 hour, then async should suffice and if your bandwidth is sufficient, then in you should only be a second or 2 behind.