Thanks for posting this Johan, I tried unsuccessfully to handle GZip files for the reasons you state and resorted to uncompressed. I will try the Lzo format and post the performance difference of compressed vs uncompressed on EC2 which seems to have very slow disk IO. We have seen really bad import speeds (like worse than mini macs even with the largest instances) on postgis and mysql with EC2 so I think this might be very applicable to the EC2 users.
Cheers, Tim On Tue, Mar 3, 2009 at 9:32 AM, Johan Oskarsson <[email protected]> wrote: > Hi, > > thought I'd pass on this blog post I just wrote about how we compress our > raw log data in Hadoop using Lzo at Last.fm. > > The essence of the post is that we're able to make them splittable by > indexing where each compressed chunk starts in the file, similar to the gzip > input format being worked on. > This actually gives us a performance boost in certain jobs that read a lot > of data while saving us disk space at the same time. > > http://blog.oskarsson.nu/2009/03/hadoop-feat-lzo-save-disk-space-and.html > > /Johan >
