3.1.2 Matrix Server Administration Guide

Chapter 18: SAN Maintenance 223

The Management Console typically displays an alert message when a

server loses access to the SAN. (See Appendix B for more information

about these messages.)

Membership Partitions

Matrix Server uses a set of membership partitions to control access to the

SAN and to store the device naming database, which includes the global

device names for SAN disks imported into the matrix. Typically, the

membership partitions are created when you install Matrix Server.

When a membership partition is placed under Matrix Server control,

write access is disabled to prevent accidental corruption from other

applications.

The following commands can be useful in diagnosing or repairing

problems with the membership partitions:

•The mxsanlk command reports the status of the SAN ownership locks

used to control access to the SAN. These locks are stored on the

membership partitions.

•The mxmpconf command starts a user interface that can be used to

create a new set of membership partitions or to repair the existing

partitions.

Display the Status of SAN Ownership Locks

Matrix Server uses a set of disk-based data structures called SANlocks to

protect filesystem integrity. If a problem causes a matrix to split into two

or more network partitions, the SANlocks ensure that only one of the

resulting network partitions has access to the SAN.

Each SANlock is stored in a membership partition. Before a matrix can

begin accessing the SAN, it must first acquire a majority of the SANlocks.

The SANlocks are acquired in order.

mxsanlk displays the status of the SANlock stored in each membership

partition. It can be used to determine whether any of the membership

partitions need to be repaired. Also, if a network partition occurs,

mxsanlk can be used to determine which network partition has control of

the SAN.