vfsrecycle_kid

From my reading elsewhere on the forum, i see that i should have enabled the "Duplication Space Optimizer" balancer.
I will do that now and let you know how it goes.

No. If, and only if, the entire Pool had a fixed duplication factor then it *could* be done. E.g., 1TB of free space means you can save 0.5TB of net data with x2 duplication or .33TB with x3 duplication etc. However, as soon as you mix duplication factors, well, it really depends on where thre data lands, doesn't it? So I guess they chose to only show actual free space without taking duplication in mind. Makes sense to me. Personally, I over provision all my Pools (a whopping two in total ;D) such that I can always evacuate the largest HDD. Peace of mind and coninuity rules in my book.

You'll want to open diskmgmt.msc and from there right click the drives in an order that does not produce conflicts.
 

 
See: http://wiki.covecube.com/StableBit_DrivePool_Q6811286
 
If you don't want WXYZ to be seen at all, then you do not need to give them drive letters (DrivePool will still be able to pool them together) - Instead of clicking "Change" simply click "Remove" when dealing with the drive letters.
 
Probably the easiest order to do this if you want to keep every drive with drive letters:
 
Change F to D Change E, G, H, I to W, X, Y, Z Change J to E (now that E has been freed up)  
Probably the easiest order to do this if you want the pooled drives to have no drive letter:
Change F to D Remove Drive Letters E, G, H, I (see my picture for the Remove Button) Change J to E --
 
You should be able to keep DrivePool running during this whole transition phase (you don't need to remove drives from the pools). Personally I'd go with Option 1. While there are Folder Mounts that you could use, I think it would just be easiest to keep everything easily accessible the "normal" way. Plus without Drive Letters you won't be able to add non-pooled content to the pooled drives (just incase you wanted to do that)
 
Hope it helps

You'll want to open diskmgmt.msc and from there right click the drives in an order that does not produce conflicts.
 

 
See: http://wiki.covecube.com/StableBit_DrivePool_Q6811286
 
If you don't want WXYZ to be seen at all, then you do not need to give them drive letters (DrivePool will still be able to pool them together) - Instead of clicking "Change" simply click "Remove" when dealing with the drive letters.
 
Probably the easiest order to do this if you want to keep every drive with drive letters:
 
Change F to D Change E, G, H, I to W, X, Y, Z Change J to E (now that E has been freed up)  
Probably the easiest order to do this if you want the pooled drives to have no drive letter:
Change F to D Remove Drive Letters E, G, H, I (see my picture for the Remove Button) Change J to E --
 
You should be able to keep DrivePool running during this whole transition phase (you don't need to remove drives from the pools). Personally I'd go with Option 1. While there are Folder Mounts that you could use, I think it would just be easiest to keep everything easily accessible the "normal" way. Plus without Drive Letters you won't be able to add non-pooled content to the pooled drives (just incase you wanted to do that)
 
Hope it helps

Sounds good. Thanks for the background info.
 
Successfully pulled out and formatted the two removed drives, and replaced them with 2 new 8TBs. No issues to report.
 
Thanks again for the great product. Made a potentially scary problem very easy to handle.