This value is requested on every upload when there are multiple zones.
Since this will result in an RPC call to every remote disk this scales
quite badly in a distributed setup. Load every 1second interval.
2 servers, localhost only. In large distributed setups much bigger
gains can be expected.
```
Operations: 21743 -> 22454
* Average: +3.28% (+0.0 MiB/s) throughput, +3.28% (+11.9) obj/s
* Fastest: +3.37% (+0.0 MiB/s) throughput, +3.37% (+13.0) obj/s
* 50% Median: +3.03% (+0.0 MiB/s) throughput, +3.03% (+11.2) obj/s
* Slowest: +8.03% (+0.0 MiB/s) throughput, +8.03% (+22.8) obj/s
```
For easy management of this a generic helper has been added.