JBoss Data Grid 6.1: High Availability, Faster Recovery: Page 2
of 2  More significant for system uptime is cross-data-center
replication, which permits nodes to be activated based on
traffic patterns, time of day or other parameters. This
capability allows far-flung servers to remain synchronized and
immediately responsive to database requests in the event of
primary node failure. "This keeps the network elastic and highly
available," said Johnson. "[Administrators] can add and remove
nodes on demand, and any one entry can be replicated to more
than one node," he said. "You can have multiple owners and set
the number to however many are necessary. And if any node
crashes, the data's still there and requests are rerouted
accordingly." This also simplifies so-called rolling upgrades
and updates, which can be done without downtime.  "This is
extremely useful for disaster recovery," said Rice.
"Environments I've worked in have to warm up the caches after a
fail-over, and that can take a substantial amount of tim