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More than ten years ago I wrote a post on Why Dynamic Disks are a bad choice… but they are still used too much without know the impact.

Microsoft Windows Dynamic Disks (or Dynamic Volumes) are an abstraction layer (introduced in Windows 2000) over the partitions (similar to the LVM layer on Linux environment) to decoupled the volumes (with their NTFS data) from the disk partitions and have a greater flexibility, like hot-extend a volume by simple add new partitions (but also several other advantages).

It’s something really old and obsolete… you can hot-extend a also a basic volume (from the GUI starting with Windows Server 2008/Windows Vista) and also basic volumes are an abstraction level.

What is really unique of dynamic disks is the “RAID software” implementation, but you can replace with Storage Spaces.

There are a lot of post that say that convert to dynamic disk could be a good idea.

Yes, converting to a dynamic disk will enhance the performance of your Windows computer. It will help you to create countless volumes to save a massive amount of data if you use the dynamic disk as a boot drive to run heavy programs.

Totaly wrong and false.

First: the operation is irreversible… you can convert from basic to dynamic, but not the opposite (without loosing data or using third party tools)

Second: if you add partitions to an existing dynamic volume you can cause I/O fragmentation, unpredictable performace (if partitions cames from disks with diffent performance), issues with applications (like backup product), possible filesystem corruptions…

Third: dynamic disks are depraced by Microsoft!

For all usages except mirror boot volumes (using a mirror volume to host the operating system), dynamic disks are deprecated. For data that requires resiliency against drive failure, use Storage Spaces, a resilient storage virtualization solution. For more info, see Storage Spaces Overview.

So… just think twice before use it!