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Creating file systems on Solaris

Before installing IBM MQ , 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

To determine the size of the /var/mqm file system for a server installation, consider:

Storage requirements for IBM MQ also depend on which components you install, and how much working space you need. For more details, see Disk space requirements.


Creating a file system for the working data

Before installing IBM MQ, create and mount a file system called /var/mqm which is owned by the user mqm in the group mqm ; see Set up the user and group on Linux. This file system is used by all installations of IBM MQ on a system. If possible, use a partition strategy with a separate volume for the IBM MQ data. This means that other system activity is not affected if a large amount of IBM 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 IBM MQ installation to match the permissions required by the queue manager.


Creating separate file systems for errors and logs

We 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.

We can protect the stability of your queue manager by having separate file systems for:

In the case of /var/mqm/errors, it is rare that this directory receives large quantities of data. But it is sometimes seen, particularly if there is a severe system problem leading to IBM MQ writing a lot of diagnostic information in to .FDC files. In the case of /var/mqm/trace, files are only written here when we use strmqtrc to start tracing IBM MQ. We can obtain better performance of normal IBM MQ operations (for example, syncpoints, MQPUT, MQGET of persistent messages) by placing the following on separate disks:

In the rare event that you need to trace an IBM MQ system for problem determination, we 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 we 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.