Tuesday Oct 30, 2007
Tuesday Oct 30, 2007
Why are are we virtualising, is it to have fewer servers, then we are consolidating. Is it to improve server utilisation and efficiency.
We have systems that can run multiple applications, we have been doing this since 1980's. Ever heard of an OS scheduler.
Have we made the mistake to put each application on it's own server. Who bought all those small servers, why. Are we fixing the server sprawl problem.
So in the late 90's and early 2000's we consolidated to large servers. Then we thought that many smaller servers were cheaper and fasters. Now we have figured out that they were not. But we do not want to admit that big consolidated servers was the right idea. So we can put a a virtualisation spin on it and consolidate again.
As I have always said, rightsizing, downsizing and funsizing.
Now a couple questions that we should ask ourselves before we go down the virtualisation route.
Can we meet the peak workload requirements, if all applications need all resources simultaneously. When we consolidate we need to be careful. The finance types will probably look at average utilisation. But, do not use average utilisation as a measure, you need to be there for the peaks. Think about this, most metropolitan underground train systems are built to cope will peak loads not average passenger traffic.
Therefore virtualisation is all about capacity planning and understanding you application workload.
Now, do we also map all of our critical applications/services and make sure that they do not run on the same server, with many virtualized partitions. Lets no put all of our eggs in one basket, we have to spread our business critical apps accross servers, computer rooms sites etc.
Stragely enough we have been able to do this on single servers running one operating system where we use priority groups and memory fencing to increase utilisation for the last 30 years. What has changed ?
So if you do not want to spend lots of money to try this and if you want to try some new high performance, multiple core, low power servers. You can get virtualisation software here for free.
Virtualisation is not new, reduce your risks and costs.