Disk has now run out of space, even though allocated storage was set?

Either you have a configured log rotation or you redirected logs to the file (in this case you need to search in the log file instead) or you have disabled a filewalker on start.

Unlikely.

and I can confirm that on my nodes.

$ grep walk /mnt/x/storagenode2/storagenode.log | tail
2023-11-09T12:00:09Z    INFO    lazyfilewalker.used-space-filewalker    starting subprocess     {"process": "storagenode", "satelliteID": "12EayRS2V1kEsWESU9QMRseFhdxYxKicsiFmxrsLZHeLUtdps3S"}
2023-11-09T12:00:09Z    INFO    lazyfilewalker.used-space-filewalker    subprocess started      {"process": "storagenode", "satelliteID": "12EayRS2V1kEsWESU9QMRseFhdxYxKicsiFmxrsLZHeLUtdps3S"}
2023-11-09T12:00:09Z    INFO    lazyfilewalker.used-space-filewalker.subprocess Database started        {"process": "storagenode", "satelliteID": "12EayRS2V1kEsWESU9QMRseFhdxYxKicsiFmxrsLZHeLUtdps3S", "process": "storagenode"}
2023-11-09T12:00:09Z    INFO    lazyfilewalker.used-space-filewalker.subprocess used-space-filewalker started   {"process": "storagenode", "satelliteID": "12EayRS2V1kEsWESU9QMRseFhdxYxKicsiFmxrsLZHeLUtdps3S", "process": "storagenode"}
2023-11-09T16:33:41Z    INFO    lazyfilewalker.gc-filewalker    starting subprocess     {"process": "storagenode", "satelliteID": "1wFTAgs9DP5RSnCqKV1eLf6N9wtk4EAtmN5DpSxcs8EjT69tGE"}
2023-11-09T16:33:41Z    INFO    lazyfilewalker.gc-filewalker    subprocess started      {"process": "storagenode", "satelliteID": "1wFTAgs9DP5RSnCqKV1eLf6N9wtk4EAtmN5DpSxcs8EjT69tGE"}
2023-11-09T16:33:42Z    INFO    lazyfilewalker.gc-filewalker.subprocess Database started        {"process": "storagenode", "satelliteID": "1wFTAgs9DP5RSnCqKV1eLf6N9wtk4EAtmN5DpSxcs8EjT69tGE", "process": "storagenode"}
2023-11-09T16:33:42Z    INFO    lazyfilewalker.gc-filewalker.subprocess gc-filewalker started   {"process": "storagenode", "satelliteID": "1wFTAgs9DP5RSnCqKV1eLf6N9wtk4EAtmN5DpSxcs8EjT69tGE", "process": "storagenode", "createdBefore": "2023-09-19T17:00:07Z", "bloomFilterSize": 364472}
2023-11-09T16:42:38Z    INFO    lazyfilewalker.gc-filewalker.subprocess gc-filewalker completed {"process": "storagenode", "satelliteID": "1wFTAgs9DP5RSnCqKV1eLf6N9wtk4EAtmN5DpSxcs8EjT69tGE", "process": "storagenode", "piecesCount": 610788, "piecesSkippedCount": 0}
2023-11-09T16:42:39Z    INFO    lazyfilewalker.gc-filewalker    subprocess finished successfully        {"process": "storagenode", "satelliteID": "1wFTAgs9DP5RSnCqKV1eLf6N9wtk4EAtmN5DpSxcs8EjT69tGE"}