If you are moving large files, use the shiftc command instead of cp or scp. An online NAS service can help diagnose your remote network connection issues, and our network experts can work with your specific file transfer problems.

For fastest file transfer between NAS /nobackup and Lou, log into Lou and use shiftc, cxfscp, or mcp. A simple cp or tar will also work, but at slower speeds.

Moving large amounts of data efficiently to or from NAS across the network can be challenging. Often, minor system, software, or network configuration changes can increase network performance an order of magnitude or more.

If you are experiencing slow transfer rates, try these quick tips:

• NAS /nobackup are mounted on Lou, enabling disk-to-disk copying, which should give the highest transfer rates. You can use the shiftc, cp, or mcp commands to copy files or even make tar files directly from NAS /nobackup to your Lou home directory.
• If using the scp command, make sure you are using OpenSSH version 5 or later. Older versions of SSH have a hard limit on transfer rates and are not designed for WAN transfers. You can check your version of SSH by running the command ssh -V.
• For large files that are a gigabyte or larger, we recommend using shiftc. This application allows for transferring simultaneous streams of data and, when used without the --secure option, doesn't have the overhead associated with encrypting all the data (authentication is still encrypted).
• Another reliable option for large file transfers is through the Shift transfer tool, which includes options specific to the NAS environment, such as checking to see whether files residing on Lou are also on tape.

One-on-One Help

If you would like further assistance, contact the NAS Control Room at support@nas.nasa.gov, and a network expert will work with you or your local administrator one-on-one to identify methods for increasing your transfer rates.

To learn about other network-related support areas see End-to-End Networking Services.