Thin/Virtual Provisioning and Windows 2008 Formatting Confusion

disk-format-ntfs

Lately there’s been some confusion about how Quick Format differs from a Full Format in Windows 2008.   To understand it fully, first let’s go back to Windows 2003 and compare that to Windows 2008.

Windows 2003 (and Windows XP)

Quick format will remove files from the partition, but does not scan the disk for bad sectors. Microsoft has stated to “only use this option if your hard disk has been previously formatted and you are sure that your hard disk is not damaged.”

Full format will remove files from the volume that you are formatting and the hard disk will be scanned for bad sectors. The scan for bad sectors is responsible for the majority of the time that it takes to format a volume.

Windows 2008 (and Windows Vista)

Quick format will remove files from the partition, but does not scan the disk for bad sectors.

Full format will remove files, scan the disk for errors, and write zeros to the length of the disk (zero filling).  This will not only lengthen the amount of time of the format, but will also destroy any thin provision or virtual provisioning benefits that your storage provider is offering.

So, if you are going to use a disk array that supports thin or virtual provisioning, make sure you understand that a full format in Windows 2008 will cause the “thin” volume to become fully allocated or “thick.”

Database and Application Considerations

Also be aware that some databases and applications also have this same tendency when creating databases and log files – such as SQL Server.

SQL Server 2005 uses the instant file initialization feature for data files (kinda like Quick format). If the data file is a log file, or if instant file initialization is not enabled, SQL Server performs zero stamping (zero filling). Versions of SQL Server earlier than SQL Server 2005 always perform zero stamping.

Learn more about EMC Symmetrix implementation and considerations for virtual provisioning here (scroll to bottom of page)

Reference: KB article 941961

Windows XP vs. Windows Vista

Why is formatting a disk so confusing?

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3 thoughts on “Thin/Virtual Provisioning and Windows 2008 Formatting Confusion

  1. Pingback: Virtual Provisioning for Exchange 2010 and Buying Groceries « Brian's Power Windows Blog

  2. Burton

    Greetings! Very helpful advice in this particular post!
    It is the little changes that will make the biggest changes.
    Many thanks for sharing!

    Reply

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