How can I improve response time on my TeamForge Lab Management box?

For speed and efficiency, consider SSH compression and forwarding many ports at once.

SSH compression

Enabling SSH's built-in compression may produce a substantial improvement in response time and throughput, especially if you are port-forwarding graphical X-Windows applications, or if you are on a slow or lossy network. Use the -C argument when setting up your SSH connections to enable compression.

The SSH command to set up a tunnel with compression is similar to setting up a tunnel without compression. For example, referring back to the command above, to set up an SSH tunnel to cu086.$vars.mgr_domain from a Linux or Solaris system through the TeamForge Lab Management Manager host $external_host, use a command like this:

ssh -C -L2222:cu086.$vars.mgr_domain:22 $external_host

Graphical SSH clients for Windows, such as PuTTY, have a checkbox to enable compression in each connection's properties.

Even if you are connecting to TeamForge Lab Management using a "fast" (T1 or better) network, we have found that you will likely still notice some improvement when using SSH compression. This is contrary to the SSH manual, which implies that it can hurt performance on fast networks. We believe the SSH manual to be out of date in this context.

If you use command-line SSH on UNIX or Windows, you may wish to default to using compression for all connections, by adding the line Compression yes to your ~/.ssh/config file. See your local SSH documentation for more details on customizing your configuration.

Forwarding many ports over the same connection with multiple -L arguments

The -L argument to ssh can be specified multiple times per line, allowing you to forward many ports with a single command. For example, consider the following command:

ssh -L 1050:cu050.$vars.mgr_domain:22 -L
1051:cu050.$vars.mgr_domain:22 -L 1060:cu060.$vars.mgr_domain:3389 -L
cu061.$vars.mgr_domain:3389 $external_host -L
1061:cu061.$vars.mgr_domain:3389

This will:

Forward ssh from cu050.$vars.mgr_domain to port 1050 on localhost
Forward ssh from cu051.$vars.mgr_domain to port 1051 on localhost
Forward remote desktop from cu060.$vars.mgr_domain to port 1060 on localhost
Forward remote desktop from cu061.$vars.mgr_domain to port 1061 on localhost