This explanation helped a lot. Got it now! Thank you!
> You start with a load of unused space -- that's the "total" for > each device in btrfs fi show. That space is allocated to specific > usages as the FS needs it. The allocated space is the "used" in btrfs > fi show for each device. > > Then we switch to looking at btrfs fi df. The "total" values are > the amount of the *allocated* space given to each type of storage. > Within those, actual stuff is stored (like your files), which is the > "used" value for each kind of storage. > > If you've ever played SimCity, the allocation process is like > zoning -- you say what kind of thing can go on the space, but it's not > actually used until something gets built on it. > > The problem you hit is when everything has been allocated, and > there's a need for more metadata space (usually), and there's lots of > unused data space. The balance operation moves some things around so > that some of the unused data allocation can be freed up, giving the FS > the ability to allocate more metadata space. -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
