Question : Maintain the some files on 2 machines in real time

Hi all

I need to maintain a directory tree equal in 2 computers in real time. The 'files' are just fully written, read and deleted. The is no need to Update the files.

Both computers are webservers receiving +-100kb files and keeping the file contend in both computer such a way that if one goes down, the service will continue to work.

For now we are considering 2 solutions, set the file content in a DB or find some distributed file system.

The part of the DB Glob, I may easily implement.

Now I don't know to qualify the Distributed File System.

I need to:
 - Every time I create a file in a Server, the file will try to copy it to the other server.
 - Every time I delete a file in a Server, the file will try to delete it in the other server.
- When a server goes down, and restarts passed some time, the system will update it self with the other server data


Now, I need to see witch Distributed File System shall I look for? I don't want to have a list of 10 of 20 different solution, that do every thing I don't need but nothing of what I need. I need a filter list of them.


I may also consider other solutions, if the work in the 2 Servers. I don't want to see more hardware to do this.

Answer : Maintain the some files on 2 machines in real time

Use DRBD in dual primary mode http://www.drbd.org/users-guide/s-dual-primary-mode.html to get bidirectional replication of block devices.

Use OCFS2 http://oss.oracle.com/projects/ocfs2/ as a cluster filesystem (support cache and distributed locks).

HOWTO: http://www.drbd.org/users-guide/ch-ocfs2.html