Speed Up Multiple SSH Connections to the Same Server
If you run a lot of terminal tabs or scripts that all need to make OpenSSH connections to the same server, you can speed them all up with multiplexing: making the first one act as the master and letting the others share its TCP connection to the server.
If you don't already have a config file in the .ssh directory in your home directory, create it with permissions 600: readable and writeable only by you.
Then, add these lines:
Host * ControlMaster auto ControlPath ~/.ssh/master-%r@%h:%p
ControlMaster auto tells ssh to try to start a master if none is running, or to use an existing master otherwise. ControlPath is the location of a socket for the ssh processes to communicate among themselves. The %r, %h and %p are replaced with your user name, the host to which you're connecting and the port number—only ssh sessions from the same user to the same host on the same port can or should share a TCP connection, so each group of multiplexed ssh processes needs a separate socket.
To make sure it worked, start one ssh session and keep it running. Then, in another window, open another connection with the -v option:
~$ ssh -v example.com echo "hi"
And, instead of the long verbose messages of a normal ssh session, you'll see a few lines, ending
debug1: auto-mux: Trying existing master hi
If you have to connect to an old ssh implementation that doesn't support multiplexed connections, you can make a separate Host section:
Host antique.example.com ControlMaster no
For more info, see man ssh and man ssh_config.
- Android Browser Security--What You Haven't Been Told
- Epiq Solutions' Sidekiq M.2
- Readers' Choice Awards 2013
- The Many Paths to a Solution
- Nativ Disc
- Download "Linux Management with Red Hat Satellite: Measuring Business Impact and ROI"
- Synopsys' Coverity
- Securing the Programmer
- RPi-Powered pi-topCEED Makes the Case as a Low-Cost Modular Learning Desktop
- Returning Values from Bash Functions
With all the industry talk about the benefits of Linux on Power and all the performance advantages offered by its open architecture, you may be considering a move in that direction. If you are thinking about analytics, big data and cloud computing, you would be right to evaluate Power. The idea of using commodity x86 hardware and replacing it every three years is an outdated cost model. It doesn’t consider the total cost of ownership, and it doesn’t consider the advantage of real processing power, high-availability and multithreading like a demon.
This ebook takes a look at some of the practical applications of the Linux on Power platform and ways you might bring all the performance power of this open architecture to bear for your organization. There are no smoke and mirrors here—just hard, cold, empirical evidence provided by independent sources. I also consider some innovative ways Linux on Power will be used in the future.Get the Guide