Database Reference
In-Depth Information
Table 4.2
vSphere Environment SQL Server-Specific Considerations
The CPU metric %RDY is the percentage of time the virtual machine was ready but
could not get scheduled to run on a physical CPU. Normally a value of less than 10% is
acceptable, but our experience has taught us that a critical production SQL Server
database is more sensitive to a lack of CPU being available, so we have lowered the
recommended threshold to less than 5%. Databases that don't have enough CPU will
cause increased response times for the end users.
The CPU metric %MLMTD has been added to the list. This is the percentage of time the
vCPU was ready to run but deliberately wasn't scheduled because that would violate
the “CPU limit” settings. It is
not
recommended that you set CPU limits. It's important
that you are aware of this metric and what it means so that you can avoid the negative
impact on database performance.
The memory metric MCTLSZ is the amount of memory reclaimed from the virtual
machine due to ballooning. A virtual machine in a vSphere environment that houses
production SQL Server databases should never be ballooning. This is a sign of the
vSphere environment experiencing memory shortages, which in turn could seriously
affect that virtual machine's database performance.
The disk metric READs/s, Writes/s you should expect to see is dependent on the type of
