Redis Mirror available capacity key is dropping below 0
pablo [11:31]
```irb(main):001:0> Gitlab::Mirror.available_capacity
=> -361
irb(main):002:0> Gitlab::Mirror.available_capacity
=> -442
irb(main):003:0> Gitlab::Mirror.available_capacity
=> -581
What this prompt tells us is that stuff is being scheduled without actually existing capacity for it, which should not be happening.
\cc @DouweM @pcarranza
Edited by username-removed-117638