OpenVMS Cluster Systems - OpenVMS Systems - HP

OpenVMS Cluster Concepts
2.7 Resource Sharing
2.7.1 Distributed File System
The OpenVMS Cluster distributed file system allows all computers to share
mass storage and files. The distributed file system provides the same access
to disks, tapes, and files across the OpenVMS Cluster that is provided on a
standalone computer.
2.7.2 RMS and Distributed Lock Manager
The distributed file system and OpenVMS Record Management Services (RMS)
use the distributed lock manager to coordinate clusterwide file access. RMS files
can be shared to the record level.
Any disk or tape can be made available to the entire OpenVMS Cluster system.
The storage devices can be:
• Connected to an HSC, HSJ, HSD, HSG, HSZ, DSSI, or SCSI subsystem
• A local device that is served to the OpenVMS Cluster
All cluster-accessible devices appear as if they are connected to every computer.
2.8 Disk Availability
Locally connected disks can be served across an OpenVMS Cluster by the MSCP
server.
2.8.1 MSCP Server
The MSCP server makes locally connected disks, including the following,
available across the cluster:
• DSA disks local to OpenVMS Cluster members using SDI
• HSC and HSJ disks in an OpenVMS Cluster using mixed interconnects
• ISE and HSD disks in an OpenVMS Cluster using mixed interconnects
• SCSI and HSZ disks
• FC and HSG disks
• Disks on boot servers and disk servers located anywhere in the OpenVMS
Cluster
In conjunction with the disk class driver (DUDRIVER), the MSCP server
implements the storage server portion of the MSCP protocol on a computer,
allowing the computer to function as a storage controller. The MSCP protocol
defines conventions for the format and timing of messages sent and received for
certain families of mass storage controllers and devices designed by Compaq. The
MSCP server decodes and services MSCP I/O requests sent by remote cluster
nodes.
Note: The MSCP server is not used by a computer to access files on locally
connected disks.
2.8.2 Device Serving
Once a device is set up to be served:
• Any cluster member can submit I/O requests to it.
• The local computer can decode and service MSCP I/O requests sent by remote
OpenVMS Cluster computers.
OpenVMS Cluster Concepts 2–15