|
May 2015 Loxoll HA-AP at COMPUTEX TAIPEI 2015 The Loxoll HA-AP storage HA appliance will be
showcased alongside Qsan Technology storage
products at COMPUTEX TAIPEI 2015! ... Learn more >> Site Isolation Protection – Part 1 of 2 What is Site Isolation? In a dual-site active-active HA
configuration, the situation where the FC connections between two clustered engines
are broken, but both engines can still see their local FC nodes (hosts and
storage), we call it an isolation of FC connectivity, or “FC Isolation”. The Loxoll HA-AP engine is designed to detect
and take over the engine cluster in the disaster situation when remote site
goes down. The FC Isolation situation will look to each local engine as if
the remote site is down, while it is only the connection between the two is
down. Effectively this results in both
engines to continue operating with their local FC nodes – each with the hosts
and storage at its own site. This is
referred to as the “split-brain” scenario. In a split-brain condition each engine will
see the local mirror member at the same site as active and the mirror member
at the other site as missing. Since
both sites continue operating under the assumption that the other site is
down, the mirror members will now start to diverge with ongoing local host
IO. Thus the mirror members’ content
will become inconsistent with each other.
This can be dangerous and undesirable.
Furthermore, problems wouldn’t become obvious immediately. Host IO at
each site will continue to run normally without any indication that the data
is “split-brained”. ... Learn more >> |
Questions?
If you have questions about
high availability solutions or this article, please contact us at:
Newsletter
Archive Click here to visit our newsletter
archive library. |