Database Reference
In-Depth Information
SQL Server database that is being housed on the environment. A batch environment
should come back with a write-intensive profile, whereas a DSS environment should
present itself as very I/O-intensive profile.
The last metric shown is DAVG/cmd. Normally for a database environment,
we like to
see a target of less than 10ms. In the case of SQL Server log files, our experience has
taught us to strive for less than 5ms. When database log files back up, it can cause an
entire domino effect on the database, thus quickly degrading overall database
performance. By their very nature, database log files are heavy on sequential write
activity. We like to recommend that log files be put on RAID-10 if available, or even
flash drives if possible. Slow log files can mean a very slow database.
Baselining the Current Database Workload
Capturing a proper baseline is one of the most important steps you will ever take to
ensure the virtualization of a production database is successful. It is very important to
understand the amount of CPU, memory, disk, and network your database will need
when virtualized. In
Chapter 10
,
we go into great detail on how to perform a proper
baseline.
When you baseline a production SQL Server database, it is very important that you
sample that database for a
complete
business cycle. Otherwise, there is a good chance
you will miss a critical workload that happens each cycle you need to account for.
Another common mistake people make is that they choose a sample set of the database
that is not taken frequently enough. The default for some of the baseline tools used out
there is one hour. A lot can happen within your SQL Server database in a short period
of time. The smaller the sample set taken of a SQL Server database, the more accurate
the baseline you will be able to build. Experience has taught us to sample CPU,
memory, and disk in your SQL Server database in 15 seconds intervals or less.
Experience has also taught us that you should take T-SQL samples every minute.
Tip
When you baseline a SQL Server database, make sure your sample interval is
frequent. CPU, memory, and disk should be sampled in 15-second intervals or
less. A lot can happen in a database in a short amount of time.
SQL Server Baseline: Things to Consider
A proper baseline of the SQL Server database is one of the most important steps you
need to take to ensure the virtualization of the SQL Server database is successful. In
Table 4.3
, which is a subset of
Table 10.2
,
we are noting specific targets for a SQL
Server database versus an overall healthy vSphere environment, as shown in
Chapter
