Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
On 03/02/2012 04:41 PM, Robinson, Eric wrote: > We have two geographically separate data centers connected by 4 x > Gigabit links (in 2 trunks). Our HA clusters are distributed between the > data centers, with each node of a 2-node cluster in a separate data > center. (In the case of our 3-node clusters, 2 nodes are in one data > center and the 3rd node is in the other data center.) Cluster membership > information is communicated though both of the Gigabit trunks, where > each trunk is a separate Corosync ring. DRBD is replicated through one > of the trunks. > > Question: If the links between the data centers are severed, split brain > will occur. What is the best way to provide quorum from a third location > out on the Internet? > > Note: I posted this question to the Linux HA list, too, because I was > not sure which was better suited. > > -- > > Eric Robinson Couple of comments; As-is, quorum can't be gained without simple majority. Thus, in a partition, your location with just one node can not become quorate. Corosync doesn't use, to my understanding, both rings at the same time. It's a simple fail-over configuration where the backup ring comes into use only in the event of a failure in the main ring. Quorum over a stretch cluster is always tricky. With sufficient speed, you could look at qdisk, but that would likely induce as many problems as it solved. -- Digimer E-Mail: digimer at alteeve.com Papers and Projects: https://alteeve.com