Right now I have a 400GB database, with a 5 node Galera Cluster. They are all RAID 10 SSDs.
I've read the following:
If the node goes missing due to a network problem or otherwise leaves without telling the rest of the cluster, then problems can arise. For the cluster to function, it needs a quorum, a majority of nodes active in the cluster. The two other nodes will continue to function normally since their partition has more than half of the known nodes but the node that left will stop accepting queries when it realizes that it is no longer in contact with the active partition. In this case, assuming an application can access the two active nodes, the failure can go mostly unnoticed.
I am trying to reduce my cost and make things more optimal. My cluster is handling a few thousand queries per minute. Is it safe to have a 3 node cluster?
What happens if 1 or 2 of the nodes go down, would there be a total outage of the database?
Is it recommended to have a 5 node cluster over a 3 node cluster?
Should I put them on RAID 1, RAID 0, or RAID 10? What is suffice?