Disk duplication, double available space?

[Lanti]

Hi Everyone! Reddit recommended me this program, after I immediately got unsatisfied with Windows Storage Spaces. I'm trying to use DrivePool to mirror two 2TB HDDs in cause of one fails in the future. As I understand from the docs, I added the two drives to the pool and enabled duplication. However, Windows Explorer and Disk Management still reporting ~3.6-3.8TB for the virtual drive created by DrivePool. Is it possible somehow to see the actual available space as a one identical drive's capacity in the two disk array "RAID 1"? Thank You!

[Lanti]

Just thinking about it, maybe double the space because the file's also counted double in the virtual drive?

[Shane]

Hi Lanti! DrivePool only reports the used, free and total size of a pool drive from the totals of the disks that form it, and the size of any given file as if it were only on one disk. There are multiple reasons for this: it's much simpler and faster to calculate, DrivePool can't guarantee that per-folder duplication settings won't be changed by the user, DrivePool's metadata is stored on the disks at varying duplication levels depending on the number of disks in the pool and this may not match the user's level(s), and reporting any other size for individual files or a pool drive can prevent Windows file operations from working properly.

I hope that helps.

[Christopher (Drashna)]

The issue is that you can have x3, x4 or higher.   And you can have it different on each folder level.  Calculating the correct size would be very expensive, in terms of resources.   Especially as some of this has to be done in the kernel, where time is critical. 

The choice was to report the "raw" size rather than the adjusted size, to make things faster and simpler.  

Unfortunately, this does mean that the size appears to be misleading.