I have two virtual machines, Host OS is ESXi 3.5 and guest OS is Centos 4.6. There are two ESXi servers remotely located, each containing a Centos 4.6 virtual machine. I wish, whatever change I make in any file/folder in one virtual machine should be automatically synchronized on other remote virtual machine. The synchronization process should be automatic. It should only sync differentials, not simulate entire copy with overwrite operation. Sync should be intelligent enough to look for what has changed and what not, and should only update the changed files/folders. Further, there should be some sort of overview and selection for syncing, for example, if it shows 4 files have changed, It should be possible to sync only two files and leave other two for the time being. So, some intelligent syncing mechanism for Linux is needed.