3.4.0 Matrix Server Administration Guide

Chapter 7: Configure PSFS Filesystems 74

The PSFS filesystem does not migrate processes from one server to

another. If you want processes to be spread across servers, you will need

to take the appropriate actions.

Journaling Filesystem

When you initiate certain filesystem operations such as creating, opening,

or moving a file or modifying its size, the filesystem writes the metadata,

or structural information, for that event to a transaction journal. The

filesystem then performs the operation.

If a server using the filesystem should crash during an operation, the

journal is replayed and any journaled operations in progress at the time

of the crash are completed. This procedure ensures that the structure of

the filesystem is consistent. Users on other servers will experience only a

slight delay in filesystem operations during the recovery.

Server Registry

Matrix Server uses a registry to control server access to PSFS filesystems

on the SAN disks imported into the matrix. A server is added to the

registry when it mounts its first PSFS filesystem.

NOTE: This registry is different from the Windows registry. The Matrix

Server registry is used only for PSFS filesystem control and is

located on the membership partitions on shared disk.

Under normal operations, a server remains in the registry until you shut

it down or remove it from the matrix. However, if a server crashes or

loses communication with the matrix and that server is in the registry

(indicating that it had active PSFS mounted volumes), Matrix Server will

remove the server’s access to the filesystems. When this situation occurs,

an alert will appear on the PolyServe Management Console,

NOSAN will

be reported for the server, and a message will be written to the Matrix

Server event log. You will need to reboot the server to restore its access.

After the server is rebooted and rejoins the matrix, it is deleted from the

registry. When the server again mounts a PSFS filesystem, it will be

added back into the registry.