Clustering

Clustering gets you live migration, moving a running guest from one node to another with no downtime, but “it just works” is doing a lot of hiding in that sentence. Live migration has real mechanics underneath it, real prerequisites that aren’t optional, and a short list of device types and configurations that simply cannot migrate live no matter how the storage is set up. Knowing which category a given VM or container falls into before you click migrate saves you from finding out mid-migration, which is the worse time to learn it. ...

Ceph shows up in every “how do I get real shared storage for my Proxmox cluster” conversation, and for good reason, it’s the one option that’s fully native, fully integrated into the Proxmox web UI, and genuinely production-grade software running underneath some very large real-world deployments. It’s also the option most likely to leave a home cluster worse off than before you added it, because Ceph’s design assumptions (plenty of nodes, plenty of network, plenty of dedicated drives) don’t bend easily to a 3-node home lab built from whatever hardware was on hand. Here’s what Ceph actually is inside Proxmox, what it needs to run well, and when it’s the right call instead of the simpler alternatives. ...

Proxmox makes joining a second node to a cluster look almost too easy, one command on the joining node and you’re done, centralized management across both boxes in the web UI. What that quick setup doesn’t make obvious is how much more you need to build on top of it before a cluster gives you the thing most people actually want from one: automatic failover when a node dies. This is the gap that catches people, they cluster two or three nodes, assume they now have redundancy, and find out during an actual outage that a VM doesn’t restart anywhere because nothing was wired up to make that happen. Here’s what clustering actually gets you, what it costs, and an honest read on whether it’s worth doing in a home setup versus running solid standalone nodes. ...