gordan@xxxxxxxxxx wrote:
Isn't that effectively the same thing? Unless there is quorum, DLM locks out the entire FS (it also does this when a node dies, until it gets definitive confirmation that it has been successfully fenced). For normal file I/O all nodes in the cluster have to acknowledge a lock before it can be granted.
Why? It requires a meta-data cache, but as long as every node in the quorum stores a given file's most recent revision # when any lock is granted, even if it doesn't actually sync the file data, then any quorum should be able to agree on what the version number of the most up-to-date copy of a file is. All nodes are required to report only if you assume that any given file has a small number of "owners" and that the querier doesn't know who the owner is.
To remain fault tolerant, this requires that servers make some effort to stay up-to-date with the meta-data cache, but maybe this could be dealt with efficiently with the DHT someone else brought up?
Regards, Derek -- Derek R. Price Solutions Architect Ximbiot, LLC <http://ximbiot.com> Get CVS and Subversion Support from Ximbiot! v: +1 248.835.1260 f: +1 248.246.1176
