fungs's questions

I am currently experiencing very bad performance using the following on an NFS network folder:

time find . | while read f; do test -L "$f" && f=$(readlink -m $f); grp="$(stat -c %G $f)"; perm="$(stat -c %A $f)"; done

Question 1) Within the loop permissions are checked using the variables grp and perm. Is there a way to lower the amount of disc I/O for these kind of checks over the network (e.g. read all meta data at once using find)?

Question 2) It seems like the NFS isn't tuned very well, the same operation on a similar network link via SSHFS take only one third of the time. All parameters are auto-negotiated. Any suggestions?

Is there any file system that can be mounted multiple times and supports concurrent file access for Linux? Basically I want something like a cluster file system but without the need to have a running network for a distributed lock manager. That can be very handy in connection with virtual machines that can share data with the host or another VM without the need to create a network link. This I want to avoid to keep the network architecture secure (virtual machine in DMZ) but share large files. No need to scale it up, just two machines that mount the same block device.

Shouldn't it be possible to have file locking information right on the disk?