The client’s view of the system is guaranteed to be up to date within a certain time bound (on the order of tens of seconds). Either system changes will be seen by a client within this bound or the client will detect a service outage.

Zookeeper does not support simultaneous consistent cross-client views. This means if a client X updates a znode from s to s’ and notifies client Y to read the updated value of the znode, then Y may read the stale value s and not s’. In order for client Y to read the latest value, it must invoke the sync operation (part of the Zookeeper API) on the znode. Zookeeper does not guarantee that different clients will always have identical views of the data, though. Due to factors like network delays, one client may perform an update before another client gets notified of the change.