Wednesday, November 29, 2006

Netadmin: Basic vs. Dynamic disks

I fielded a question about dynamic disks today - "If I'm using a hardware RAID configuration, is there any advantage to converting from a basic to dynamic disk configuration?".

The short answer is No.

Dynamic disks essentially provide for a software RAID solution. They change the partitioning table, and were introduced in the Windows 2000 timeframe. If you have a hardware RAID solution, there's no reason to convert to dynamic disks. Step back and for a second and think about it for yourself... if the hardware RAID is transparent to the OS (and it is); adding a software RAID on top of the hardware RAID would serve what purpose? Added complexity, increased risk of corruption, and decreased performance.

If you have a hardware RAID controller use it. Pass on the dynamic disks.

More information in a KB article can be found here.


Teo Heras said...

I don't like dynamic disks either and often hear the argument that you can used dynamic disks to extend the partitions. Well, you can do this as well with basic disks as. If you add an additional hard-drive and it appears as unallocated space, you can extend the partition using diskpart.

Volume expansion using diskpart


Nick said...

That’s a good point - you can provision additional storage capacity easily using diskpart. Just throw a few drives in, provision them in a supportable hardware RAID configuration (using your Dell, HP, etc. management tools), then you can use diskpart to extend the filesystem of one of your volumes onto the new capacity of the additional disk. And since the RAID configuration is invisible to the OS, drives can still be failed/replaced without the OS complaining, or your extended file system caring.

Anonymous said...


Well a good reason to use dynamic disks is that most controllers and even lots of NAS/SAN's will not let you create partitions larger than 2 TB. So when you need a partition that is larger add a those hardware RAID X protected virtual disk to Windows, turn them into dynamic disks and voila ... you can get way larger partitions. This works with smaller disk as well ... get the protection from the hardware and get the single disk experience from dynamic disks. Disk duplexing is another reason to use dynamic disks. You can get controller reduncancy that way. I'm least likely to use Dynamic disks for the system partition due to the contraints they impose in felxibility and on my bag of recovery tools.