XtreemFS is a distributed and replicated file system for cloud and grid infrastructures; clients and servers can be distributed worldwide.

XtreemFS builds a reliable storage system from standard off-the-shelve components through replication. The complexity of geographic distribution and replication is transparently provided as a POSIX file system. Applications and users do not see a difference in the API and semantics compared to local file systems.

The research focus for XtreemFS is on techniques for efficient and fault-tolerant replication, large scale snapshots and backups as well as monitoring, automatic tuning and healing.

As part of XtreemFS, we also develop BabuDB, an LSM-tree based database which is used for storing metadata in XtreemFS.

Further details:
http://www.xtreemfs.org/