I heard that GFS NFS failover prevents data loss. Is that true?
No, it’s not true. What it prevents is data corruption as a result of the node waking up and erroneously issuing writes to the disk when it shouldn’t. The simple fact is that no one can guarantee against loss of data when a computer goes down. If a client goes down in the middle of a write, its cached data will be lost. If a server goes down in the middle of a write, cached data will be lost unless the filesystem is mounted with “sync” option. Unfortunately, the “sync” option has a huge performance penalty. GFS’s journaling should minimize and/or guard against this loss. With NFS failover, if a server goes down in the middle of an NFS request (which is far more likely), the failed NFS service should be failed over to another GFS server in the cluster. The NFS client should get a timeout on its write request, and that will cause it to retry the request, which should go to the server that has taken over the responsibilities of the failed NFS server. And GFS will ensure the original serve
