Examples of Sync Commands and Output

Sync Command Examples

  1. Continuous synchronization of a daily archive of large files on a Windows machine to Linux machine, preserving Windows acls, run as an async pull on the Linux machine:
    $ async -L /sync/logs -N backup -d /sync/backup -r alligator@everglades.company.com:"C:\data\" -i /.ssh/lion_private_key -K pull --remote-scan-interval=4h --preserve-acls=metafile --remote-preserve-acles=metafile -C --exclude-dirs-older-than=1w0d0h0m0s


    • Logs are stored on the Linux machine in the specified location.
    • The user, lion, authenticates with an SSH key using the -i option
    • Because the files in the backup are large, remote-scan-interval is used to scan the Windows machine every 4 hours, which forces an additional scan in case any notifications are missed.
    • In order to preserve Windows acls in the backup, both preserve-acls=metafile and remote-preserve-acls=metafile must be specified.
    • Since the archive directory creates a new directory for each day, use exclude-dirs-older-than=1w0d0h0m0s to avoid scanning directories that are no longer changing (older than a week).
  2. High performance push synchronization of many (10,000s) of small files (<10 KB) between Windows machines:
    > async -L c:/logs:200 -q -N small-files -c none --pending-max=10000 --preserve-acls=native --transfer-threads=4 -R c:/logs:200 -d c:/data/ -r bobcat@"C:\data\" -K push -l 500m


    • Specifying the logging locations (-L and -R) is optional. Adding :200 to the end of the log directory value allows the logs to reach 200 MB before being rotated.
    • If the connection is secure, disabling encryption using -c none may boost performance.
    • Increase the number of pending files from the default of 2000 using --pending-max=10000.
    • The --preserve-acls=native option preserves Windows ALCs.
    • Using more FASP threads to move the data can improve performance, set with --transfer-threads=4. The number of threads should not exceed the number of CPU cores (the lower value of the client and server machines).
    • The user must enter the password at the prompt because it is not provided in the command. Aspera recommends using SSH keys for authentication, but this is not required.
  3. Non-continuous bidirectional synchronization of directories containing a mix of large and small files in which small files are synced using one thread and large files use another, run on a Linux machine to a Mac OS X machine:
    $ async -L /sync/logs -q -N sync-2017-01-01 -d /images --user=gazelle@company.com --host= -r Library/data/images -i /lion/.ssh/lion_private_key -R Library/sync/logs --transfer-threads=2:100k -K bidi


    • Logs are saved in the specified locations on both machines.
    • The user authenicates with an SSH key using the -i option.
    • The user and host are specified as separate options, rather than as part of the destination folder, so that the username with an @ can be used (@ is reserved in an -r argument for specifying the host).
    • The sync uses two threads, one for files larger than 100 KB and one for files less than or equal to 100 KB, specified with the --transfer-threads option.
  4. Non-continuous push synchronization through reverse Aspera Proxy:
    $ async -N pushproxy -d /images -r lion@ --proxy=dnats://gazelle:password@ -K push


    • The transfer username on the destination ( is lion, the proxy IP address is, and the proxy username is gazelle.
    • The Proxy URL option must include the proxy user's password.

Sync Output Example

When Sync is run in interactive mode, the status of each file in the synchronized directory is displayed in a list similar to the following:

/file1                        SYNCHRONIZED
/file2                        SYNCHRONIZED(exs)
/file3                        SYNCHRONIZED(skp)
/file4                        SYNCHRONIZED(del)

The status may be one of the following options: