Much has been said and written about how important it is for networks to
be highly available and how critical it is for a business, given the
pace at which an enterprise network grows, and how the dynamics keep
evolving and changing over time.  When the networks grow to accommodate
the demands of an expanding enterprise business, the enterprise
monitoring needs seem to get more and more complex.  Delivering high
availability and disaster recovery is the mantra to successful,
uninterrupted enterprise network monitoring. In this post, lets see how
the high availability of an enterprise network can be ensured..

Ensuring high availability

To ensure uninterrupted enterprise network monitoring, a contingency
plan detailing what must be done when there is a system failure or a
site failure or maybe even a mishap, is essential. Before we proceed, it
helps to understand that a thin line differentiates ‘failover’ from
‘disaster recovery’. Failover is a method employed by most enterprises
to ensure that the system availability is resumed within an acceptable
time-frame, whereas, ‘disaster recovery’ is a fallback strategy when all
the failover strategies break.  Different enterprises employ different
failover strategies that can be broadly categorized into cold, warm, or
hot standbys, based on what is acceptable to their business.

As the enterprise business (and even those of SMBs) depends largely on
the availability of various services, there are no two ways to
continuous, uninterrupted network monitoring. As an administrator, you
would look at the network monitoring software’s ability to quickly
failover in the event of, say, a server crash, which by the way, is one
of the myriad possibilities that can lead to interrupted and incomplete
monitoring.  The worst of scenarios is where the entire site goes down
due to a power outage, or owing to a natural phenomenon like an earth
quake or a tsunami (fortunately such events are far and few between and
hope that no one gets to suffer such a nightmare!). Whatever maybe the
case, disaster preparedness is the only sure-shot way for a business to
stay alive.

Failover for Enterprises

In the case of large enterprises, a cold or warm standby will not cut
it. A cold start warrants manual intervention and warm start involves a
backup running in the background with the data being mirrored to a
secondary server at specified intervals. It is possible that the data on
both servers is not synchronized all the time.  A hot standby becomes a
clear gating factor for a software that manages fault and network
performance of critical systems and services.

A hot standby failover is preferred because,

 i) the redundant systems run in parallel with a 100% data synchronization

ii) the users do not experience a glitch as the failover is smooth and almost instant.

Hot-standby in OpManager

More on setting-up single-site and multi-site redundancy in another post..

You Can Learn More About the ManageEngine Product Line By Going to manageengine.optrics.com

The original article/video can be found at Uninterrupted Enterprise Network Monitoring