ISN’s technical consultants have put their heads together and come up with some practical advice for IT teams considering introducing virtualisation.
1 - Start small and work up
So that you and your team can familiarise yourselves with the concepts and issues around virtualisation, start with free or inexpensive tools like #Citrix #XenServer, #VMware ESX3i or VMware Workstation.
Try For your first production systems try running simple server workloads like Blackberry Enterprise Server, DHCP or secondary domain controllers.
2 - Take a phased approach
Don’t try to do everything all at once. Trying to do too much in one step is a recipe for downtime and disaster. Specialist consultancies can provide the tools and expertise to help you plan the best way to get to your desired end results.
3 - Don’t expect to be able to virtualise all of your systems
Sometimes you are better off with physical servers. Direct attached storage in the form of RAID arrays on an intelligent caching disk controllers will often give better performance for high throughput databases than virtual machines accessing shared iSCSI storage.
4 - Check compatibility of existing software applications
Confirm with vendors that their applications are supported on virtual machines and consider their recommendations when looking at server, network and backup options.
5 - Don’t forget about licensing
Remember OEM licenses are tied to the hardware they were bought with, so that you can’t simply convert a machine running OEM software and stay compliant. Each virtual Windows server or desktop would need its own operating system license - either volume or retail box.
6 - Think about backup and recovery up front
Although it is easier to back up and restore, a production virtual machine needs a proper rigorous backup regime in place to allow quick recovery from data loss. Choose products which are designed for virtual systems such as those from Vizioncore or Symantec.
7 - Upgrade hardware warranty
When you are running multiple production virtual machines on one physical server system, this become vital as any downtime is compounded. For HP servers ISN recommend 24/7 6 hour Call-to-repair or 4 hour response Carepack warranty extensions. Dell too offer a “4 hour Mission Critical” response add-on to their basic warranty.
8 - Build a solid foundation for the future
Don’t try to skimp and put your first production virtual machines on a low-end system as this will generally become your production environment before you know it. Hardware is cheap compared to the cost, disruption and inconvenience of rebuilding. There is also a cost to eroding users’ confidence in new systems by providing it on under-powered hardware. Choose reliable, fast server hardware with redundancy built in.
9 - Use shared storage for more flexibility
For non critical server workloads with very little data it is feasible to keep the data within the virtual machine. To get the most out of a virtual environment, realising the full benefits of disaster recovery, resilience, flexibility and performance, it is best to separate critical production data and locate it on a shared Storage Area Network (SAN) or high end Network Attached Storage (NAS) device.
10 - Plan network capacity for best performance
ISN use iSCSI or fibre channel accelerators in servers attached to a separate storage LAN with a dedicated switch fabric to guarantee fastest data access times and throughput between servers, shared storage and users. If your server uses the same LAN for iSCSI access to a SAN as it does to serve data to users, problems can arise.
11 - Use outside expertise to give you a head start
It can save a lot of time and money to use an experienced consultancy to get you started on your virtualisation project. ISN’s qualified consultants can help you get results fast and transfer practical skills to your own IT team.
If you have any questions about virtualisation or how it might work in your business, please leave a comment or call me at ISN on 020 7313 9900.