The maxdirsize is the maximum size of a directory in a FlexVol or FlexGroup volume. It is determined by the number of inodes allocated to the directory. If the directory contains more files than the maxdirsize can accommodate, then the ONTAP software will return an out of space error message to the host, even if the volume has enough free space. This can happen when a FlexGroup volume has a flat directory structure with millions of files, as the maxdirsize is not automatically adjusted for FlexGroup volumes12. References: 1: FlexGroup volumes: Frequentlyasked questions | NetApp Documentation 2: How to increase the maxdirsize of a FlexVol volume - NetApp Knowledge Base