It does not delete it but its recommended you back up your data first
 
Also Defrag it, before you do
 
If you want to switch back to basic disk it will delete the data

Even if the drive is currently partitioned with primary and extended partitions?
 
Basically, I dont see any reason not to convert to dynamic then? Right? I could convert, and then freely change my partition sizes.
 
Correct?

A small word of warning:
 
My firend used dynamic disks, on his RAID setup. He had a separate partition for Windows. Now, he just got a new mobo/CPU/RAM, so he figured, wipe the system partiton, reinstall, and you're good to go. But with dyunamic disks, the partitoin info is kept on the system partiton, so he jsut lost 160GB worth of data. He's been working with a recovery program for a couple days trying to get his data back.
 
Just a warning,
-bZj

There is always a risk of resizing partitions - especially FAT and NTFS - Linux seems to handle it ok. I once changed my harddisk to dynamic, i found through a benchmark that the average transfer rate of the harddrive was reduced, and it gt slower, and slower, and s.l.o.w.e.r.......
 
and finally crashed. I've never trusted it ever since.

Hmm, I just used the import Foreign Disk(s) under the Disk Management console and it worked fine for me. New install and everything on a different RAID controller. I then copied the data over to said new array and then wiped the old dynamic drives away...

A word of waning when using Dynamic Discs.
 
If you convert Basic Disks to Dynamic discs and then decide to say change OS or use a program other that Disk Management you will either not be able to change/install anything, crash the utility/OS Installer or lose all you data because dynamic discs don't use partitions.
 
Trust me I used dynamic discs then tried to convert from FAT32 to NTFS and not only did it fail and destroy all my data it made it unrecoverable.