I am having a really hard time trying to understand the concept behind corosync and clustering. Maybe some charitable soul will feel sorry for me and explain it simple enough.
So, we have two identical servers running proxmox, and I want to have redundancy for some virtual machines, so that in case one of them fails, the other server will take over and start working. Each server has plenty of local disk space, so I mounted the vm in the local disk (actually a raid11 disk setup). I then added a third smaller proxmox machine for quorum to have HA.
Then I migrated the VM from the first server to the second server. I thought (and I now think I am completely wrong) that this migration process would duplicate the information on the first server to the second server, keeping them synced from then on. But actually that does not seem to be the case, once the vm is migrated, the vm disappears from the first server.
From further reading, I now "seem" to understand that a cluster needs shared storage for that to be true. Please confirm if I finally get the idea.
However, this makes me wonder: why would I need to use a cluster if there´s a single point of failure anyway there ? Except that the point of failure is not the server but the shared storage.
Thanks for your comments.
So, we have two identical servers running proxmox, and I want to have redundancy for some virtual machines, so that in case one of them fails, the other server will take over and start working. Each server has plenty of local disk space, so I mounted the vm in the local disk (actually a raid11 disk setup). I then added a third smaller proxmox machine for quorum to have HA.
Then I migrated the VM from the first server to the second server. I thought (and I now think I am completely wrong) that this migration process would duplicate the information on the first server to the second server, keeping them synced from then on. But actually that does not seem to be the case, once the vm is migrated, the vm disappears from the first server.
From further reading, I now "seem" to understand that a cluster needs shared storage for that to be true. Please confirm if I finally get the idea.
However, this makes me wonder: why would I need to use a cluster if there´s a single point of failure anyway there ? Except that the point of failure is not the server but the shared storage.
Thanks for your comments.