• 6 Posts
  • 60 Comments
Joined 1 year ago
cake
Cake day: June 1st, 2023

help-circle





  • To clarify on the terminology: You’d be adding a second node to a cluster.

    As to what it gives you: Going from 1 node to 2 nodes gives you some extra compute power to run your workloads. It does hower not increase reliability of the cluster, for that you’d need a minimum of three nodes. At that point you’ll have quorum, and will be able to take down any one node while still maintaining a quorum for cluster consistency. Quorum is half your nodes rounded up, so for 2 and 3 nodes the quorum is 2, for 4 and 5 nodes the quorum is 3, etc. In other words, a simple majority of nodes needs to be up for the cluster to be able to “vote”. Then you’ll be able to do fun things like load balancing, shared storage, etc.

    As for how to add nodes to a cluster - here’s the documentation.







  • Donwside to 2: Your VM becomes harder to move between hardware, you lose snapshotting capabilities from a copy-on-write image.

    5 is flexible, but has limitations. For example you wouldn’t want to run databases on NFS volumes.

    If initialization time is the only problem with 4, you could create several smaller images on the disk. Create the first one, initialize the VM and set up an LVM volume on it, then start creating more volumes and extend the LVM volume.