System Administrator Interview Cheat Sheet

* nslookup has been deprecated by its makers for years now.

* ip route's replaced 'route', which still works but won't show you all the things that ip route can.

* Nothing on dot1q VLAN tagging, which is pretty common these days

* No CDP from hosts, which is also pretty common

* No Postfix or any other non-Sendmail mailer.

* The somewhat bizarre 'bash script to validate RPM files'. Why not just teach the proper query syntax or, for scripting, RPM & yum APIs?

* Solaris.

If you're being asked these questions, or your interviewer is expecting these answers, you may wish to consider whether you want the role.

"How do you check disk usage. How do you trouble shoot a high disk usage issue"

which is fine, until someone's done something similar to the next bit of advice - i.e. deleted some "old", large files that were still open by the application.

Better: compare filesystem usage (with df), against disk space used (with du), to deduce that there's an open file that has been unlinked. Then use lsof (whatever Sun say about pfiles or about dtrace, lsof is an essential tool) to look for processes with open files that have large offsets.

And, when deleting large files, check whether they're open, and truncate them before deleting them if you're not sure.

(note to another poster - ain't nothing wrong with Solaris! But I'm not really sure what interviewer might ask questions about the OSI 7 layer model, these days, and I agree that there's a real odd jumble of scripting snippets in there: best advice to anyone wanting to improve that side of their systems administration skills, is to read a copy of Unix Power tools.)

Frankly, the Solaris & NIS+ questions are useless. You will not use either in a modern web startup, unless you're doing something wrong. Ditto for the AIX questions, LPARS, HP-UX, and Power-VM sections.

Ask a sysadmin questions relevant to your environment, or where you want your environment to go. Don't expect them to be a domain expert in every single region, and don't give weight to domain expertise irrelevant to your startup. I coached a friend through a phone interview with a generic LAMP-based startup recently whose hiring consultant spent an hour asking him questions about BGP, OSPF, Solaris, VMWare and EMC specific SAN devices.

The interviewer was a typical big company/academic systems administrator who had no startup experience. It was pretty ridiculous, these questions were asked by the interviewer because that's what his expertise was in, not because any of these were ever going to have any relevancy for this startup.

He passed, of course, and now their whole environment are AMIs.

I will say that I think any systems administrator today who isn't excited about learning Puppet or Chef is the wrong choice for a web startup.