3.1.2 Matrix Server Administration Guide

Chapter 1: Introduction 7

The PSFS filesystem provides the following features:

• Concurrent access by multiple servers. After a filesystem has been

created on a shared disk, all servers having physical access to the

device via the SAN can mount the filesystem. A PSFS filesystem must

be consistently mounted either read-only or read-write across the

matrix.

• Support for standard filesystem operations such as mkfs, mount, and

umount. These operations can be performed either with the

Management Console or from the command line.

• Support for existing applications. The PSFS filesystem uses standard

read/write semantics and does not require changes to applications.

• Quotas for users and groups, including both hard and soft limits.

• Journaling and live crash recovery. Filesystem metadata operations

are written to a journal before they are performed. 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. Users on other servers will experience only a slight delay

in filesystem operations during the recovery.

Matrix Server Databases

Matrix Server uses the following databases to store matrix information:

• Shared Memory Data Store (SMDS). The SANPulse daemon stores

filesystem status information in this database. The database contains

cp_status and sp_status files that are located in the directory

/var/opt/polyserve/run on each server. These files should not be

changed.

• Device database. The SCL assigns a device name to each shared disk

imported into the matrix. It then stores the device name and the

physical UID of the disk in the device database. The database is

located on the membership partitions that you selected when

installing the Matrix Server product. (The membership partitions are

also used for functions related to SAN control.)