November, 2009
Improve performance on small hadoop clusters
Hadoop is designed to run on huge clusters containing several hundred machines. But some people just don’t need such a big cluster and are able to use the benefits of HDFS and MapReduce on a smaller scale. We managed to improve performance of our 10-node-test-cluster by almost 100% by adjusting the heartbeat intervals. Namenode and [...]
“Internet slow” on Ubuntu Karmic Koala (9.10)
“Internet slow” means actually “DNS slow”. After upgrading to Ubuntu 9.10 I experienced a strange and very annoying lag in DNS resolution. Running dig in a shell worked like a charm. But Firefox, Synaptic and everything else was hanging at DNS resolution. To make a long story short (you probably read a lot of forum [...]