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■MANAGEMENT: ADVICE
has enabled the prioritisation of recovery actions, behind the move towards virtualisation, the decision
typically foreseeing the recovery of most systems process will include the following considerations:
over one to five days • When to virtualise? Are you due to refresh the hard-
• Where they exist, testing of recovery plans is not ware?
performed as often as it should be. According to the • Which virtualisation software? VMware, Xen or
Business Continuity Institute, more than 50pc of Hyper-V?
recovery plans are untested. Is this a form of denial? • Which virtualisation hardware?
‘It won’t happen to us.’ • How much hardware do you put in the recovery site?
• What SAN and is it compatible with the virtualisa-
Growing expectations tion platform?
Perhaps it’s because we live in an age of instant • What backup software and is it compatible with the
communications that there appears to be more virtualisation solution?
‘disasters’ which cause interruptions to businesses – or • Which servers should/can be virtualised?
perhaps there really are more. Either way, both • Which servers require a physical environment and
customers and employees are increasingly expecting are there any issues mixing physical and virtual?
that organisations can: • Do you do it yourself or outsource? Consider training
• Recover from a business interruption within 24 costs and staff retention
hours • Do you perform incremental backups or mirror?
• Ensure no data loss or corruption What’s your RPO and RTO (recovery time objective)?
• Continue to provide the same level of service as prior
to the incident. Challenges
Once the decision to virtualise is taken, then more
Enter virtualisation challenges emerge that can impact IT philosophy and
Although virtualisation has been around for more than governance fundamentally if all the benefits of virtual-
four years, it is only in the past 12 months that its isation are to be realised. Strict processes and proce-
adoption has hit mainstream. A complementary tech- dures will need to be implemented to address:
nology, storage area networks (SAN), has also been • Standardising server templates. Setting the rules
evolving and often a decision to use virtualisation can • Which operating systems are allowed on which
drive the need to revisit the storage architecture. Both virtual machines
technologies together increase server and storage util- • Change management. Keeping your recovery plan in
isation and enable elegant backup and recovery solu- sync with production
tions. From a disaster recovery point of view, organisa- • Critical patch deployment during an incident
tions that have implemented a virtualisation solution • Testing the recovery plan.
can expect:
• To recover all servers in the optimum sequence within If you are engaging third parties and/or a remote DR
24 hours site as part of your recovery plan, then you should
• To recover the desktop environment within hours consider:
• No loss of data, depending on the storage solution • Recovery servers’ proximity to the recovery centre
implemented and production (this may impact data replication
• To be able to test recovery without affecting the choices)
production environment • Telecommunications links: bandwidth, redundancy
• To reduce energy consumption and increase safety and resiliency
margins in the computer room air conditioning • If you are using a third party’s hardware, ensure
(CRAC) equipment. compatibility
These benefits assume good management of the IT • Is there sufficient hardware to host all applications?
environment and good disaster recovery planning. • Support for your virtualisation environment. Ensure
The virtualisation software enables fast server setup, no dependency on single individuals.
but success is dependent on having up-to-date config- Gartner estimates the cost of downtime to be
urations, a thought-out, programmed sequence of between ¤14,500 and ¤6.5m per hour, depending on the
recovery, compatible systems and more (see Challenges size of the company. So, if the consequence of downtime
below). is substantial and the RTO is consequently short, and
you’d like to get most applications up and running
Decisions, decisions quickly, then virtualisation is a potential solution. But
So, if virtualisation answers all the problems, why isn’t you would miss opportunities to reduce risk in other
everybody doing it already? Well, there are costs asso- areas if you only considered using virtualisation in your
ciated with it and potential re-architecting required. DR plan. Virtualisation is a strategic decision and
Change means risk and this needs to be understood should be taken with the whole IT picture in mind. The
and dealt with appropriately. The decision to virtualise benefits are significant, the costs are not insignificant
cannot be taken independently of other architectural and the risks are outweighed by the opportunities
and management issues. Whatever the driving force virtualisation enables.
68 Knowledge Ireland September 2008
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