When a multi-volume file system is created, all volumes are dataonly, except volume zero, which is used to store the file system's metadata. The volume availability flag of volume zero cannot be set to dataonly.
As metadata cannot be allocated from dataonly volumes, enough metadata space should be allocated using metadataok volumes. The "file system out of space" error occurs if there is insufficient metadata space available, even if the df command shows that there is free space in the file system. The fsvoladm command can be used to see the free space in each volume and set the availability flag of the volume.