Archive for the 'System Administration' Category

MySQL Performance Tuning on Centos 5.1

Saturday, May 17th, 2008

Last week I installed SugarCRM for arsenic.ph to try it out. While I was playing around with adding new users and roles, I noticed that it took over a minute for SugarCRM to finish creating one user. I began investigating and slow queries notwithstanding, MySQL turned out to be the performance bottleneck. This server is still new and I still have not come around to tuning MySQL as I have already begun moving most of my work to Postgres. Unfortunately there are still a large number of good software packages out there that require MySQL so I was left with no choice but to tune it.

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On the Recent Debian OpenSSL Debacle

Friday, May 16th, 2008

I can think of only two words that best describe the whole deal: Epic fail.

It’s been quite a spectacle ever since I saw that security vulnerability report on the NVD RSS feed. Even though the bug has been patched and fixed, system administrators are now left with the task of cleaning up the mess. It would have been OK if it only affected Debian and Debian-based systems. But it turns out the damage is far reaching. Even if you don’t run Debian, if you are using SSL certificates generated by a CA who generated the certificate using a Debian system, your SSL certificate will have to be revoked and replaced! See here.

Amazing what a couple of lines of code can do.

Getting Postfix to run SMTPS on port 465

Sunday, April 27th, 2008

While setting up my new server, I followed the guide found here. Because of SmartBro’s braindead policy of forcing its subscribers to use their flaky SMTP server, I am forced to work around this issue by running SMTPS instead. I followed Step 5 of the guide and I was wondering why Evolution could not connect to the server. I have already enabled port 465 to go through on Bastille firewall but running nmap on the server does indicate that Postfix was not listening on port 465 as it should be.

I even went as far as regenerating my self-signed SSL certificates to be sure I had everything buttoned down. This just another one of those face-in-palm moments where the cause of the problem was so obvious. I forgot to enable SMTPS in master.cf. I simply uncommented the following lines in master.cf:

smtps     inet  n       –       n       –       –       smtpd
  -o smtpd_tls_wrappermode=yes
  -o smtpd_sasl_auth_enable=yes
  -o smtpd_client_restrictions=permit_sasl_authenticated,reject

Then I restarted Postfix and nmap now reports port 465 open.

Feels Like Christmas Came Early This Year…

Saturday, April 26th, 2008

Got a new server a couple of days ago and I just completed upgrading iwojima to a new version of Ubuntu. I’m now running Ubuntu 8.04 LTS on the desktop and all I can say is that it’s a step forward for Linux on the desktop. I still can’t wrap my head around the reason for making Mozilla Firefox 3 Beta 5 the default browser on an LTS (Long-term Support) release. But it looks like it was a good decision to do so. The only thing missing are some key extensions that I use a lot, such as Firebug and the Del.icio.us extension.

For a Beta release, Firefox 3 is pretty solid and feels really fast. I haven’t had nspluginwrapper crash on me yet, as opposed to the previous version which would crash from time to time especially when viewing sites with multiple Flash movies. Hopefully, Evolution mail client crashes have been fixed in this LTS release. It’s caused me a lot of grief before when it would crash randomly and then keep crashing when I restart it.

Desktop effects still suck though. When I enabled it, I still get that ugly black screen flash whenever I start Firefox. The new clock applet finally supports multiple timezones, very useful since I deal with clients in different timezones.

Two apps the I use a lot, Wine and Cinelerra, both have repositories for 8.04 so it looks like I have everything I need. Overall it feels like a solid release worth of the “LTS” designation.