# `Ankusa.Health.Check.Disk`
[🔗](https://github.com/jamescarr/ankusa/blob/ankusa-v0.7.0/packages/ankusa/lib/ankusa/health/check/disk.ex#L1)

`disk`, with `listener.ready_min_free_bytes` set (YAML `node.min_free_bytes`): the file
system holding `data_dir` has at least that many bytes free. Below it the
reason is `below_floor`, and the node is unready *before* the store hits
`ENOSPC`, which is what lets the load balancer drain it while the operator
still has room to act.

Free space comes from `:disksup` (`:os_mon`), which core does not start and
the server image does. A floor with no `:disksup` running, an answer that is
not a disk entry, or one that takes longer than `@timeout_ms` (a hung mount)
is reason `unmeasured`: a configured floor that cannot be checked fails, it
is never silently skipped.

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*Consult [api-reference.md](api-reference.md) for complete listing*