DRBD-reactor is one of our younger projects, but did you realize it’s already three years old?
For some projects, three years is not a lot, but drbd-reactor does what it should and has reached a state of stability — both from the point of view of feature completeness and that it has been a while since anyone has found a bug.
At the same time, our headaches with Pacemaker remain. It’s difficult to support because the logs are too noisy; it has some unintuitive concepts, and its membership layer (Corosync) might detect membership changes at a different pace than DRBD.
So, moving forward, LINBIT will change our communications and express a clear preference for drbd-reactor over Pacemaker in our documentation, tech guides, blog posts, etc.
You might counter by saying that Pacemaker can do two-node HA clusters, while drbd-reactor requires three nodes at minimum. But in detail, you need fencing/stonith for a Pacemaker two-node HA cluster. The cost and effort for implementing fencing/stonith are higher than adding a third node.
You may also counter that every reasonable server now comes with a BMC and is manageable over IPMI, so there is no additional cost for implementing stonith. However, an independent, dedicated network is crucial for fencing purposes.
Then, we are at the point where a third node, which does not need all the storage, might be a VM in a nearby virtualization system, which might be as small as a Raspberry Pi. Then you see my point that a third node is cheaper than fencing/stonith for a two-node cluster. On top of that quorum, enabling quorum is foolproof – enable a boolean configuration option. Fencing/stonith, on the other hand, is a complicated dance that can easily be broken for many reasons.
Moving on, we noticed mentions of our software in two separate places. Andrei Kvapil discusses DRBD and LINSTOR in ‘You don’t need an operating system, you only need Kubernetes.’
Also, 45Drives referenced us a few times in a recent YouTube video. They used our documentation on iSCSI HA clustering for their Corosync and Pacemaker configs and adapted it for RBD because our solution proved to perform better than the competition.
If 45Drives sounds familiar, it’s because we wrote about the company using our software for an academic research clustering project with Nova Scotia Community College (NSCC) in April, which you can read about on our blog.
As shared in my previous newsletter, we held our Q2 Community Meeting on the 13th, which you can now watch here. We have another event just around the corner, hosted by our friends at Vates. The joint webinar will discuss the next update to Xen Orchestra 5.95, and you can find more information and register here.
Recent software releases include drbd-9.1.21 and drbd-9.2.10, which covers the fix of two regressions we discovered. Also, WinDRBD 1.1.15 fixes a rare corner case where Windows starts swapping out kernel mode thread’s stacks. Finally, linstor-proxmox v8.0.3—The proxmox-csi-plugin uses a naming scheme that was not covered by linstor-proxmox. This release fixed this.
