How to assign FULL space in VM disk

[VladoB]

Dears,

 

I created VM and created disk of 1TB in size, but when I check .img file, I see that it is small and it is enlarged as needed. I believe that for spped purposes it is better to assign full space to .img file since beginning.

 

Am I right?

 

And if so, how I can force unraid to create .img with full size since beginning?

 

Many thanks

 

V

[Kilrah]

If you want to dedicate the full drive to the VM you should pass the whole drive instead of making a vdisk. 

 

 

[VladoB]

I see, so for .img file it is not possible, right?

[Kilrah]

If you create the image file manually and make it qcow2 you can apparently have it preallocated:

https://serverfault.com/questions/428868/does-kvm-raw-images-support-preallocation

 

Believe that'll simply write to the whole image so it'll take hours, and you could do the same yourself in your existing vm by just writing into a temp file until the disk is full.

 

Doubt you'll see any performance improvement from doing either of them though.

[VladoB]

Hi, I am not sure I am given option to create is as qcow2?

[Kilrah]

You can select qcow2 in the VM template editor, yes.

But what I meant was that instead of having the image automatically created by unraid you'd need to previously manually create it from the command line to be able to supply those arguments.