Creating file systems on UNIX and Linux systems
Before installing IBM® WebSphere® MQ Version 7.5, you might need to create file systems for both the product code and working data to be stored. There are minimum storage requirements for these file systems. The default installation directory for the product code can be changed at installation time, but the working data location cannot be changed.
Determining the size of a server installations file system
- The maximum number of messages in the system at one time.
- Contingency for message buildups, if there is a system problem.
- The average size of the message data, plus 500 bytes for the message header.
- The number of queues.
- The size of log files and error messages.
- The amount of trace that is written to the /var/mqm/trace directory.
Creating a file system for the working data
Before
you install IBM WebSphere MQ,
create and mount a file system called /var/mqm which
is owned by the user mqm
in the group mqm
;
see Setting up the user and group on UNIX and Linux systems. This file system is used
by all installations of IBM WebSphere MQ on a system.
If possible, use a partition strategy with a separate volume for the IBM WebSphere MQ data. This
means that other system activity is not affected if a large amount
of IBM WebSphere MQ work
builds up. Configure the directory permissions to permit the mqm
user
to have full control, for example, file mode 755. These permissions
will then be updated during the WebSphere MQ installation to match
the permissions required by the queue manager.
Creating separate file systems for errors and logs
You can also create separate file systems for your log data (/var/mqm/log) and error files (/var/mqm/errors). If possible, place these directories on different physical disks from the queue manager data (/var/mqm/qmgrs) and from each other.
If you create separate file systems the /var/mqm/errors directory can be NFS mounted. However, if you choose to NFS-mount /var/mqm/errors, the error logs might be lost if the network fails.
- /var/mqm/errors
- /var/mqm/trace
- /var/mqm/qmgrs
- /var/mqm/log
- /var/mqm/qmgrs
- /var/mqm/log
In the rare event that you need to trace a IBM WebSphere MQ system for problem determination, you can reduce performance impact by placing the /var/mqm/trace file system on a separate disk.
If you are creating separate file systems, allow a minimum
of 30 MB of storage for /var/mqm
, 100 MB of storage
for /var/mqm/log
, and 10 MB of storage for /var/mqm/errors
.
The 100 MB minimum allowance of storage for /var/mqm/log
is
the absolute minimum required for a single queue manager and is not
a recommended value. The size of a file system must be scaled according
to the number of queue managers that you intend to use, the number
of pages per log file, and the number of log files per queue manager.
For more information about file systems, see File system support.
The size of the log file depends on the log settings that you use. The minimum sizes are for circular logging using the default settings. For more information about log sizes, see Calculating the size of the log.
- Linux and Solaris
- For a client installation, the file system can be mounted on a remote network device, for example NFS.