Command line reference : fmsadmin commands : BACKUP command
 
BACKUP command
Format
fmsadmin BACKUP [FILE...] [PATH...] [options]
Description
Backs up the specified databases (FILE) or all the hosted databases in the specified paths (PATH).
By default, the BACKUP command performs a live backup of a hosted database, without interfering with client usage. Alternatively, first PAUSE the databases, then issue the BACKUP command, followed by a RESUME command to perform an offline backup. If you don’t specify a destination path, the databases are backed up to the default backup folder. If you don’t specify a database or folder to back up, all hosted databases are backed up.
Each time you use the BACKUP command, FileMaker Server creates a new subfolder within the default backup folder or the specified backup folder. The name of the new folder is the local server date and time when you use the BACKUP command.
You can use options to verify and clone your backup file after the backup has completed. A clone of a database contains all the field definitions, tables, layouts, scripts, and page setup options, but none of the record data.
Options
-d path, --dest path
path overrides the default backup folder destination by backing up the databases to the specified path. If the path doesn't exist, FileMaker Server attempts to create it. The path to a folder must end with the slash (/) character. For example:
Windows: filewin:/driveLetter:/folderName/
OS X: filemac:/volumeName/folderName/
-k number, --keep number
number is an integer specifying the maximum number of backups to keep (the default is 1). FileMaker Server creates time-stamped subfolders in the specified destination folder, removing the oldest folder when the maximum number has been reached.
If number is 0, then FileMaker Server places the backup file directly in the specified destination folder without creating a time-stamped subfolder. Any backup files with the same name are overwritten.
-n, --clone
Clone each backup file after backup and optional verify are completed.
-x, --verify
Verify integrity of each backup file.
Related topics 
RUN command
Database and backup folder settings
Command line reference