Consider using nfs
to mount remote filesystem on a server.
On server B, you may set /etc/exports
as follows:
# See exports(5) for a description.
# This file contains a list of all directories exported to other computers.
# It is used by rpc.nfsd and rpc.mountd.
/folder/to/export SERVER_A_IP(rw)
Then, start nfs
service and, from server A you may use:
mount -t nfs SERVER_B_IP:/folder/to/export /mnt/mountpoint
However, your question should have been posted on ServerFault. I flagged it as off topic, hope they move it.