Drbd manual split brain recovery

 · 1. Start drbd manually on both nodes (Go to both drbd primary and secondary servers and run the below command) /etc/init.d/drbd start –version lower than CentOS7 systemctl start drbd –for CentOS7. 2. Define one node as secondary and discard data on this. drbdadm secondary all drbdadm disconnect all drbdadm -- --discard-my-data connect all 3. If you get degraded DRBD with log messages like “Split-Brain detected but unresolved, dropping connection!”, you have to manually resolve split brain situation. Possible reason for such situation. You switch all cluster nodes in standby via cluster suite (i.e. pacemaker) at the same time, so you don’t have any active drbd instance running.  · Graceful recovery from split brain if one host has had no intermediate changes. In this mode, if one of the hosts has made no modifications at all during split brain, DRBD will simply recover gracefully and declare the split brain resolved. Note Estimated Reading Time: 8 mins.

In order to be able to enable and configure DRBD’s automatic split brain recovery policies, you must understand that DRBD offers several configuration options for this purpose. DRBD applies its split brain recovery procedures based on the number of nodes in the Primary role at the time the split brain is detected. This is split brain with unrelated ancestor generations, thus auto-recovery strategies, even if configured, are moot. DRBD disconnects and waits for manual split brain resolution. No UUIDs match Finally, in case DRBD fails to detect even a single matching element in the two nodes’ GI tuples, it logs a warning about unrelated data and disconnects. Manual Split Brain Recovery Let’s say we had a network problem which caused our DRBD fall into a “Split Brain” mode. If this happened we can find something like “ kernel: block drbd1: Split-Brain detected but unresolved, dropping connection! ” in /var/log/messages.

Mar So in that case - yes - you have to resolve that manually. The question that arises to me is why did these concurrent accesses happen? Dec Log in to the secondary node as root locally (or remotely using SSH) to access the Console menu. · Invalidate the DRBD. · Reboot the secondary. Manual split brain recovery. DRBD detects split brain at the time connectivity becomes available again and the peer nodes exchange the initial DRBD protocol.