Error messages for diskspace issues?

I recently banged my head against the desk repeatedly when trying to clone a site between spokes. I kept getting an error message saying that the tar.gz (from the backups directory) could not be extracted.

Running: gunzip -c /var/aegir/backups/sitename-stamp.tar.gz | tar pxf - in /var/aegir/platforms/platformname/sites/sitename

Failed to extract the contents of /var/aegir/platforms/platformname/sites/sitename to @target (The file could not be extracted)

I'm thinking this message isn't terribly helpful! :)

Naturally I jumped to "permissions" as the culprit, and spent way too much time checking and double-checking all of the relevant permissions, before a colleague asked if there was enough diskspace on the spoke. It turned out that in fact I was running out of diskspace for my backups on the hub, and the tar.gz was being written, but incompletely. Once I freed up some space for the backups, I got a proper backup.tar.gz file from the clone process, and everything went smoothly.

A simple explanatory error message would have made this much easier to deal with, but also it seems like the clone/migrate should fail earlier than it does. Rather than waiting to try to extract the backup, could there be a quick integrity check when the file is created in the first place?

Looking forward to discussing this, thanks.