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Failover Clustering queries


We are planning to setup failover clustering on windows server. We are currently having sql server 2016 standard edition.

I have few queries in mind.

Do we need to move on to enterprise edition/ sql 2019 before configuring clustering nodes, in case we want to move on future so is it better to move on before configuring clustering or its independent process ?
What happens when main node(server/instance) goes down?
How will the other node come up?

If we do maintenance/weekly updates(hardware/sql/software) on one node, how will it replicate/effect other
node too?

What happens if we restart one node? How will it sync with other node?
5. In case one node goes down, what about the transactions running on that node?

  1. Do we need to backup all data (full bckp,diff,trans log) separately or clustering takes itself in its functionality?

I need a bit of idea so that we decide the process of setting it up.




You can setup an FCI instance using Standard Edition - up to 2 nodes for the instance. In this configuration you have shared storage between both nodes and only one instance of SQL server - which is installed into the cluster.

Since this is shared storage - a failover changes ownership of the storage to the new node and starts SQL Server on that node. Since this is shared storage - there is no replication of data required.

This is different from Availability Groups which requires separate instances on each node - and synchronization of data across all nodes. A BAG (basic availability group) can be configured for Standard Edition - but it is very limited (single database - one secondary).

In an FCI - restarting the node that is not hosting the instance has no impact on SQL Server (unless you have a problem with the cluster configuration). Restarting the node that is hosting SQL Server forces a failover to the other node.

To your last question - backups are completely separate from clustering. You must setup maintenance tasks to backup your databases regardless of clustering. That is also true of an AG - you cannot and should not rely on having a secondary as a backup strategy. If any database is set to full or bulk_logged recovery then you must perform frequent (as in every 15 minutes or so) log backups.

I would recommend hiring a consultant to help you setup a clustering solution and mentor/train you on how to manage and maintain the cluster.