Database Reference
In-Depth Information
recommend the use of a tool such as vCOPs that can provide longer-term trending and
reporting analysis of the data.
Test/development is where we do not see customers using memory reservation for any
SQL Server virtual machines and allowing the hypervisor and the built-in memory-
reclamation features handle memory.
Remember, the previously provided guidance to those just starting off with SQL Server
virtualization. These shops are usually defined by skilled vSphere administrators who
have done a great job virtualizing applications and skilled DBAs who are good at
running SQL. What we don't have is a shop with vSphere administrators skilled at
running SQL on vSphere and DBAs skilled at running on the vSphere platform. This is a
way to ease into the journey and build a foundation before undertaking more advance
actions.
Once the environment is running for several business cycles and consumers are satisfied
with the performance of the systems, we begin the discussion of modification of the
initial implementation. We recommend that analysis be performed on the systems to
determine if further actions, such as removing reservations in the Tier 1 environment,
should take place. Yes, we do have customers who run large Tier 1 databases in
production without reservations. These are vSphere admins who have built a trust and
understanding with the DBA team to provide the resources necessary to the SQL
Servers and DBAs who are upfront and honest about the resources necessary to run
these systems.
SQL Server: Min/Max
As we peer into the SQL Server virtual machine, there are some memory-specific
settings we will mention here, but these are covered in much more granular detail in
Chapter 7 . Why is memory configuration important? Simple, to minimize the number of
reads and writes that need to go to physical media. It may seem obvious, but we will
mention it now: Accessing data from memory is faster than accessing data from disk.
The first item to consider is the use of the Sql Server Min Server Memory / Max Server
Memory setting to create a memory buffer pool for SQL Server. The Min setting
establishes the lower boundary and the Max setting establishes the upper boundary. The
default setting for Min Server Memory is 0. The default setting for Max Server Memory
is 2,147,483,647MB. If you do not change these settings, SQL Server will dynamically
manage memory requirements based on the availability of system resources. Based on
the availability of resources, SQL Server will release or acquire memory dynamically.
From our travels, we've found that most DBAs prefer to configure these settings
themselves. When setting these parameters, keep in mind the following: The SQL Server
buffer pool will begin to acquire memory and keep this memory up until the Min Server
Memory value is reached. Administrators will use this setting to configure a minimum
 
 
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