Local disks are the disks that are only connected to a single node. They are, therefore, not protected against node failure (not highly available). However, all disks, including local disks, are included in the global namespace and are configured as global devices. Therefore, the disks themselves are visible from all cluster nodes.
You can make the file systems on local disks available to other nodes by putting them under a global mount point. If the node that currently has one of these global file systems mounted fails, all nodes lose access to that file system. Using a volume manager lets you mirror these disks so that a failure cannot cause these file systems to become inaccessible, but volume managers do not protect against node failure.
See the section Global Devices for more information about global devices.