Database Reference
In-Depth Information
This will ensure that in a cluster with N+1 hosts locally (to allow for HA), you will
always be able to restart the largest VMs and perform maintenance.
Figure 10.4
illustrates this point. On the fourth host is a VM with 48GB RAM. Overall,
the cluster has sufficient resources for HA Admission Control. Assuming all the memory
of each VM is reserved, there is nowhere for the large VM on the fourth host to restart if
that host were to fail. The fourth host in this case would also not be able to enter
maintenance mode.
Figure 10.4
vMotion Slot Size example.
Summary
This chapter covered both infrastructure and application baseline activities related to
SQL Server 2012. Much of the information covered could be applied to other versions
of SQL Server, or even completely different applications. It provided you with the
why
,
when
,
what
, and
how
of measuring the baseline successfully, and how to ensure you at
least meet if not exceed your system's required performance when virtualized. When
virtualizing SQL Server databases, especially large and business-critical databases, it's
important that you reduce risk and eliminate guesswork as much as possible. You want
to virtualize but you don't want to compromise—be it performance, availability,
recoverability, or any other SLA. If that is your goal, then baselining your workloads is
critical.
The real measure of your success will be when your databases are virtualized and meet
or exceed the requirements set out at the start of the project. You will never know that
without a good baseline to measure from. If you do this part of your job well, your
