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Turn on Instant File Initialization for SQL Server Performance

Without Instant File Initialization turned on, each time a data file on SQL Server 2005 and above is created or has to grow in size, the file or portion of the file added must be zeroed out.  Depending on the size of the file this can be a very time consuming task.

By turning on Database Instant File Initialization, you are telling the operating system to trust SQL Server to properly handle this allocation.  Since you are looking to enable Instant File Initialization you should also consider setting a proper auto growth setting for your database.  Something in MB verses percentage.  This should be a fail safe, you try to implement some type of policy or procedure to monitor the amount of free space in your databases and try to grow them after hours.

While there isn’t an option within SQL Server to turn this on, the process is very simple.  You simply have to add a SQL Server group to a security policy.  To find which group to add you need to run lusrmgr.msc on the workstation or server in question.  Click on Groups, marked with a RED arrow on the top left of the image below.  Then look for the group that states “specified instance of SQL Server”  This is highlighted in the image below.  The group in my experience has nearly always been “SQLServerMSSQLUser”, plus Machine Name, then Instance Name.  Take note of this group (write it down) as you will need to add it to a local security policy.  You can now close out of lusrmgr.

Next click start, run and type SECPOL.MSC.  The dialog box in the image below will open up.  Expand “Local Policies”, click on “User Rights Assignment”, then scroll down the list of Policies until you see “Perform volume maintenance tasks”.  Double click on “Perform volume maintenance tasks”.

Click on “Add User or Group”

Click on “Object Types”

Uncheck all boxes except for “Groups” and click “OK”

Next make sure that “Locations” is your local workstation or server name, not the Active Directory Domain.  Next click “Advanced” and chose “Find Now”, a list of groups should now appear.  This is where you will scroll down the list and find the group you determined from above (lusrmgr.msc).  In my example it is “SQLServerMSSQLUser$WIN-LJDS9D9PTAA$MSSQLSERVER”.  Once you have selected your group click “OK”

You should now see your group listed.

Click “OK” and then “OK” one last time.  That is it. You can now close the Local Security Policy window.  When your database grows or when you add additional files, you should no longer have the long waits of the system having to zero out the additional space.  Want to see a live demo of this, check out my Youtube Channel

Additional things to note is
1) You could just grant access to the SQL Server Service account, however if this Service Account is ever changed you will have to go back and add the new account to the Security Policy.  Which ever way works best for you.  The important thing is to just have it on.
2) By not zeroing out the file there could possibly still be data that could be read.  This is a very slight security risk and there are only a few scenarios where this could pose a risk.  The average Joe could not access the data.
3) Instant File Initialization only works for your data files, it does not have any impact to your LOG files.

Want to see a live demo of this, check out my Youtube Channel


Tim Radney - Database Professional

Tim Radney - Database Professional by Tim Radney I am a Sr DBA for a top 40 US bank. I live in the south eastern US. I have been working with database since 1999 but only full time for the past three years.


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