Database Reference
In-Depth Information
driver you should consider for your SQL Server database is the Paravirtual SCSI
driver.
Physical World Is a One-to-One Relationship
In the physical world, there is a one-to-one relationship between applications and
hardware. The reason we say “one-to-one relationship” is that it is very typical to have
a separate server to host each key application. For example, a server to host Microsoft
Exchange and another physical server for your production SQL Server database would
be common. As you can see, there is typically one physical server for each major
application. There is also a lot of unused capacity/resource when there is one server
dedicated for each major application.
One-to-One Relationship and Unused Capacity
How often is each one of those dedicated physical servers busy seven days a week, 24
hours a day? It has been the authors' experience that across an organization, it is not
very likely the servers are fully utilized seven days a week, 24 hours a day. This is
further compounded by the mindset of always having spare capacity just in case. Here is
a personal example of that mindset in play.
Years ago, I worked for a very prestigious hospital. My database was on a very large
server. At times we would be doing intensive processing within the database and start
to pin the CPU in the 90%-100% range. When I say “pin,” just to be clear I mean the
CPU utilization would stay above 90% for long periods of time. The system
administrator (SA) would come running into my office to figure out what was going on.
He did not like to see the CPU get above 60%. I, on the other hand, like the idea that if I
buy a computer, I am taking full advantage of its capabilities. The SA's way of thinking
was commonplace in my experience. Other SAs might have higher thresholds, but they
still like to see very ample spare capacity. I wonder if management realized they were
buying computers at that hospital that had almost twice the computer capacity they really
needed. Could that money have been put to better use elsewhere in the organization?
That mindset is one of the many reasons we tend to have dedicated servers for each
major application.
In the SA's defense, if he needed more resources, they were not easy to come by. Unlike
a virtualized platform, where adding another CPU is a click away, at that hospital
another CPU was not a simple click away. If it was not sitting there idle, it could not be
added easily. My grandfather used to have a saying: “When they keep telling you about
the good old days, don't believe them. I lived them. They were not that good. People
died from lots of things we can prevent today, we did not have air-conditioning, and a
car beat a horse and buggy any day.” Well, times have changed, and so has technology.
We can choose to live in the past or embrace the now.
