Category Archives: Systems Administration

Tuning JVM Memory Settings

By Timothy Creswick | Published: November 30, 2011
Update: Andrew Wang’s blog post (http://www.umbrant.com/blog/2012/twitter_jvm_tuning.html) is a pretty nice quick guide, well worth reading in conjunction with this page. Sorting out sensible JVM memory settings in a production environment can be a tricky business. There are some great articles, blogs and lengthy white-papers out there explaining the details of how the JVM manages memory, [...]
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A more sensible PowerShell prompt

By Timothy Creswick | Published: September 5, 2009
The default PowerShell prompt is long and irritating. I switch my default to the following: In order to achieve this, I have the following script: function prompt { Write-Host("%") -nonewline -foregroundcolor Yellow; return " "; } c: cd Scripts " "; You’ll also note that I change the default working directory to C:\Scripts, which is [...]
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Use nmap to locate ProCurve switches on your network

By Timothy Creswick | Published: September 5, 2009
Nmap is a great tool; utterly indispensable for network administrators. If you haven’t got it yet goto http://nmap.org or install via your favourite package manager. Here’s one of my frequently used nmap commands – very simple, but gives you a quick list of IP addresses for all of the ProCurve switches on your network. nmap [...]
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Automated batch reboot of HP ProCurve switches via telnet

By Timothy Creswick | Published: March 26, 2009
Today I had occasion to reboot about 20 ProCurve 3500yl switches, thanks to yet another firmware bug. The simplest way of doing this is with the “reload” command issued via telnet. Rather than logging into each switch and issuing the reload command by hand I threw together an Expect script which automatically logs into the [...]
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