Does anyone know of any open source storage virtualization application that enables a cluster of computers to present a single, unified file store? That is, have you seen/heard of a "data vault" solution that provides a single, cluster-wide, hierarchichal file name space into which files can be deposited and then retrieved, generally in their entirety?

Here's what I'm after:

virtualizing: Clients connect to any available storage node, and are presented with the same file tree. The cluster software manages the placement of files within the cluster, and automatically spreads deposited files across the cluster.

extensibility: The cluster can be dynamically grown and shrunk by adding or removing machines. Adding new machines to the cluster causes the available storage pool to grow; no manual moving of files is needed. Space permitting, machines can also be quiesced and removed from the cluster under administrator control: files stored on the quiesced node are automatically migrated to the remaining, available nodes. The cluster can scale to at least 4,096 nodes, comprising a total of 12 Petabytes of storage, or more.

self-auditing ability: The cluster continually checks its own integrity to make sure that all files stored in the cluster remain available. If a disk appears to be near failure, the cluster automatically migrates all data from it and idles the disk.

Any pointers would be greatly appreciated. This must be open source.

Thanks!

I'm looking for that solution too... do you find some???

This could be what you are looking for:
http://en.wikipedia.org/wiki/Global_File_System

You mean like a NAS?

http://en.wikipedia.org/wiki/Network-attached_storage

If so, FreeNAS http://www.freenas.org and Openfiler http://www.openfiler.com and two that provide iSCSI...

Hope this helps.

Well... It's like a nas, but with the drives distributed into servers...