On Tue, 10 Jun 2025 08:50:56 +0100, Jonathan Dowland wrote: > On Mon Jun 9, 2025 at 9:45 PM BST, Celejar wrote: > >> Can you elaborate, please? Are you recommending that I just stop using >> qcow2 going forward and stick to raw? > > > Yes, if 80GiB is sufficient within the VM. > >> My understanding is that the former will generally be *more* space >> efficient, rather than *less* (in addition to providing additional >> functionality, such as snapshotting)? > > > It can be more efficient, and it can be less, as you've discovered. > > If you need functionality that qcow2 provides and raw doesn't, then > this isn't going to be a solution for you. However, converting the disk > image (even from qcow2 to qcow2) *might* result in a smaller second > disk image.
Okay - I tried running "qemu-img convert" with both "-O raw" and "-O qcow2", and I ended up with similarly sized files, about 57GB, which is the size of the actual data on the VM disk. So I'm going to continue with qcow2, and just note for future reference that I may need to do a conversion every now and then. I see now that the "qemu-img" man page actually acknowledges this: "Image conversion is also useful to get smaller image when using a growable format such as qcow: the empty sectors are detected and suppressed from the destination image." Thanks for the help! -- Celejar
