If you've been on call before, you know it's only a matter of time before you get paged when you are having dinner out, enjoying a movie, or at a party. I've been paged at all three in addition to other awkward moments. Now, it's typically considered pretty rude to pull out your laptop at dinner, at the movies or at a party unless you are with a bunch of other systems administrators. That means that when an emergency occurs you usually have to sequester yourself out in your car or somewhere private with your laptop until you can fix the problem.
What I've discovered over time is that only a small percentage of paging events actually require all of the tools on my laptop. In many cases I can respond to and solve the issue directly from my cell phone. Sometimes I can even respond more quickly. Plus, while I'm fortunate to have a 3G network card for my laptop, not every administrator has that privilege. When you can respond with a cell phone, you can get right to the issue instead of searching around for your nearest wireless hot spot.
The key to administering servers from your cell phone is a SSH client. Because most Unix administration is done from the command line, it makes sense to set up your remote administration so that it can all be done from SSH. While a number of remote console and remote power tools have Web interfaces, most of them (such as HP's iLO, Sun's ALOM) support remote serial appliances, and others also support either telnet or SSH.
There are a number of different SSH clients available for cell phones depending on your model. On my Blackberry I've been happy with MidpSSHe. It's free, and so far it has worked pretty well for me. The main thing to get used to with any cell phone SSH client is that you will likely not have the same low-latency interactive environment you are used to. A 3G network helps quite a bit, but even then you have to be patient as you wait for the commands you have typed to show up on the screen.
Another issue with cell phone SSH is dropped connections. Nothing is more frustrating than almost being finished with an issue only to have the SSH connection drop. For this reason I recommend initially logging into a remote Unix machine that has the screen utility installed. Screen allows you to maintain shell sessions that you can disconnect from and resume later. Even if your connection drops, once you log back into the machine and resume your screen session, everything will be back where you left it.
When you can respond to emergencies completely from your cell phone, you can more easily deal with the awkwardness of being paged in a social situation. For instance, if you are paged during a movie, you can simply excuse yourself and walk down to the hallway near the exit where you can still see or at least hear the movie. It sure beats walking out to the car and powering on your laptop. During dinner or at a party you can just excuse yourself to the restroom and fix the problem before anyone knew you had been paged.
One of my favorite examples of cell phone systems administration occurred when a fellow Unix administrator and I were having dinner. I got paged on an issue that basically required that I power cycle a server. I had my laptop nearby, but since both my coworker and I had our cell phones one of us logged into the serial console for the machine while the other logged into the PDU. We were able to power cycle the machine and watch it come back up before I would have been able to even boot my laptop.
With more advanced Blackberry models, iPhone and iPhone Apps, and even Google entering the cell phone market, today's trends seem to point toward people doing more and more with their cell phones. So while today you might only be able to use SSH from your phone, tomorrow could bring vendors that port their management tools directly to your cell phone and web browsers that are sophisticated enough for you to use your web-based tools as well. In the mean time I'm happy enough with the tiny green-on-black SSH terminal always in my pocket.