I have a basic cloud running on Ubuntu Server (9.04) and Eucalyptus. Walrus (Eucalyptus' API compatable S3 implementation) stores files by on the cloud controller. However each of the other 4 server have 1TB storage which is largely unused. I am looking for a way to pool all the storage together in order to make use of all available resources. I have been loooking at various options including PVFS, Lustre, HDFS (Hadoop).
My only requirments are that it need be scalable and that it runs well on Ubuntu. I would appreciate hearing from anyone who has experience with such technologies and I look forward to hearing your suggestions.