On 07/19/2012 11:10 AM, Yunkai Zhang wrote: > That is the point, they are different! > > Zookeeper driver *just* giving priority to process LEAVE event, only > when there is unfinished BLOCK event. By this difference, all sheep > will process each message in the same order, but this rule will be > broken in corosync driver.
They are different in relax degree, but compared with strict ordering, it is the same: order is relaxed. You relax the order when the queue is blocked. We don't need this rule in corosync driver, this is not the rule for sheepdog: we don't blindly stick to any stereotype unless it is proved necessary. Relax ordering is very common in distributed system, for e.g, event consistency relax the read/write ordering. What really matters is, if relaxing still provide correct behavior. As far as corosync is concerned, this relaxing is correct and give us benefit that: once confchg is handled as highest priority, we will reduce the wrong read/write requests with epoch mismatch to a very low degree, compared with strict ordering. Thanks, Yuan -- sheepdog mailing list [email protected] http://lists.wpkg.org/mailman/listinfo/sheepdog
