> > On 18 Mar 2020, at 09:15, Jérôme Barotin <[email protected]> wrote: > > Hi, > > I'm considering installing DRBD to share a filesystem in real time between > two different cloud provider (OVH & Hetzner average ping 20ms). > Both of them provide CEPH based block storage, my idea is to synchronize a > 2/3 TB sized partitions, ideally with the DRDB with protocol C in an active / > active configuration. > Do you think it's possible ?
It is about as possible as it is possible to walk through a minefield and survive. It is possible, but it is not something anyone should atttempt. Sharing a filesystem across multiple nodes requires a cluster filesystem, which requires distributed locking and also requires a dual-primary DRBD with a high-reliability replication link and reliable fencing, because any interruption of the link causes an immediate split-brain situation otherwise - also including virtual machines not answering in time, and that is also a common problem in cloud environments, because there are no scheduling guarantees and the cloud hypervisors are often highly overprovisioned. So to summarize, virtually everything in a multi-site cloud environment is the worst case scenario for a high availability cluster, especially one with a cluster filesystem, and it would probably provide higher availability to run no cluster at all (just a single machine) and fail over manually as required than trying to run a dual-primary shared-filesystem cluster across multiple cloud environments. Also, DRBD on top of Ceph doesn’t sound too right in the first place. That’s like running a Linux VM in a Windows VM on a Linux hypervisor, when you are really just using a single Linux instance. So long story short, not recommended. However, if you could tell us what use case you are actually trying to realize, we might be able to suggest a setup that does the job. br, Robert _______________________________________________ Star us on GITHUB: https://github.com/LINBIT drbd-user mailing list [email protected] https://lists.linbit.com/mailman/listinfo/drbd-user
