Database Reference
In-Depth Information
likely caused by the application. In my professional experience in the physical world,
well over 80% of database performance problems are caused by the way the
application was architected, built, or indexed.
It would be great if I could inform you that those problems are going to go away, but
they will not. Taking a poorly performing database/application and just virtualizing it
won't change anything. What performs poorly in the physical world will perform
slowing in the virtualized world, unless something has changed. Virtualization is not a
silver bullet that will solve all that ails you.
With the new capability to hot-add more RAM or to hot-plug additional CPUs, you as a
DBA need to behave differently. In the physical world, you always size the database
server with future growth in mind. You try to get the server configured with enough CPU
and RAM to last you for the next three to four years. In effect, you are hoarding
resources for a rainy day (as DBAs, we have all done it). This ensures there is always
enough spare capacity for when you needed it up the road.
In the virtual world, you live in a shared-resource realm where that physical host
contains one or more VMs on it. You have the ability to hot-add more RAM or hot-plug
additional CPUs, as needed. You have the added capacity to move VMs onto other hosts
that are underutilized or just to more effectively load balance the workload between the
physical hosts.
The VM can even contain a SQL Server database that's in use. You are able to move the
database to a different physical host that's being underutilized as the users are accessing
the database, without ever shutting it down. In this shared world, it's important that you
only ask for the resources you need. If you need more, you will be able to get more
resource quickly or reallocate how virtual machines are being used to free resources
where they are needed most.
In this new paradigm, the DBA has the ability to shut off resources that are not currently
needed. In this world of shared resources, you not only can get more resources when
needed, you have options that were never available before in terms of how resources
are used and allocated.
In this highly redundant shared-resource world, as a DBA you will get more sleep and
work fewer weekends. Think about it: The more redundant your setup is, the less your
database will fail, and the fewer times you will have to perform an unexpected database
recovery. This all translates into more sleep for you as a DBA.
Provisioning/DBaaS and Database Virtualization
It seems these days everything is a service, so why not databases? To begin this
discussion, let's put aside all our preconceived notions concerning the difficulties of
deploying databases programmatically. Let's talk about the benefits of what this type of
