When an empty namenode storage directory is detected on normal NN startup, it may not be fully initialized. The new directory is still part of "in-service" NNStrage and when a checkpoint image is uploaded, a copy will also be written there. However, the retention manager won't be able to purge old files since it is lacking a VERSION file. This causes fsimages to pile up in the directory. With a big name space, the disk will be filled in the order of days or weeks.