Archive for the ‘performance’ Category

Permgen space

Friday, January 9th, 2009

Personal note to self: use these to increase memory in JBoss and work a bit longer before you get a PermGenSpace exception.

-Xms128m -Xmx1024m -XX: PermSize=64m -XX: MaxPermSize=256m

How to lower the load average on a server with more than 50% in 10 seconds

Friday, May 9th, 2008

$uptime
… load average: 0.54, 0.40, 0.36

$sudo vim /etc/fstab
(add the noatime option)

# /dev/sda3
UUID=8623d9e3... / ext3 defaults,errors=remount-ro,noatime 0 1

$sudo mount -a

$uptime
… load average: 0.24, 0.16, 0.17

So far this completely unscientific proof.

More info about the noatime option.

Blocking bad bots

Wednesday, April 9th, 2008

Today I blocked some bad bots that were spidering some of my sites. Most notably Custo, which downloads your entire site.

An interesting solution is posted here (I used the mod_rewrite option). You can test this by changing your user agent in Firefox.

This guy seems to be following bad bots.

I added Java, Nutch, Jakarta, Vagabondo and an empty bot name to the list of bad bots.

Website Performance tuning with Firebug and YSlow

Thursday, February 14th, 2008

Today I discovered a cool plugin for Firefox: YSlow.

In combination with Firebug, it allows you to quickly get a report about performance issues with your site, like too many css or javascript files, missing cache headers and much more.

I got a score of 66 for koopjeszoeker.be! Not much to improve there, besides switching to a CDN, but I don’t think this is something that will happen very soon (maybe with Amazon S3?).