plex backup

running these exact commands work fine:

cd /mnt/myvolume24t/jails/plexmediaserver_2/var/db/
tar cvfz /mnt/myvolume24t/backup/Plex/plexdata.tar.gz plexdata

Running this single command fails:

tar -cvfz /mnt/myvolume24t/backup/Plex/plexdata.tar.gz /mnt/myvolume24t/jails/plexmediaserver_2/var/db/plexdata/