[tantalor]

Graphing "free storage" is meaningless and confusing; it should be "used storage".

Available storage depends on usage and capacity.

Edit: I meant for this article; of course I believe it is useful to track this in practice.

[fanf2]

Free storage is what matters because it makes it very obvious when you are getting close to a disk-full outage.

[AnotherGoodName]

Used makes sense for getting a feeling for pure performance (smaller the better as its likely to be in memory).

Available makes sense for knowing when things will just plain break (reaching 0 = write failure for a DB).

>Every few months we get an alert from our database monitoring to warn us that we are about to run out of space.

In this case they were avoiding their DB server breaking. They didn't do this for performance reasons.

[zufallsheld]

If you pay for a fixed amount of storage and only use it partially, you should also monitor free storage sdso you know when you waste it.