DB2 10.5 for Linux, UNIX, and Windows

User-managed file system support for DB2 pureScale environments

Although a file systems that is managed by the DB2® product is recommended, you might want to use your existing shared file system.

Currently, the only supported user-managed file system is an IBM® General Parallel File System (GPFS™) file system. For the supported GPFS versions, see the Installation prerequisites for DB2 pureScale Feature (AIX). During product installation, the DB2 installer checks whether the version of the user-managed GPFS cluster and file system is supported. If it is not supported, instance creation fails.

In addition to ensuring that you are using the correct version, you must verify your existing GPFS file system configuration. To verify the configuration of the current file system cluster, issue the following command:

   install_path/bin/db2cluster -cfs -list –filesystem

where install_path is the current file system cluster location.

To verify the file system setup, issue the following command:

   install_path/bin/db2cluster -CFS -VERIFY -CONFIGURATION -FILESYSTEM db2fs1

where mygpfs1 is the name of the existing GPFS cluster file system.

A DB2 managed file system and a user-managed file system cannot coexist. The IBM DB2 pureScale Feature supports only one DB2 pureScale instance; you use either a DB2 managed file system or a user-managed file system.

If you use a user-managed file system, the default passwordless remote root login is required.

When you create your first DB2 pureScale instance, you must provide the full path to an existing GPFS file system to indicate that you want to use a user-managed file system. The DB2 installer verifies that the file system is valid to use.

For response file installations, the INSTANCE_SHARED_DEVICE_PATH keyword represents a DB2 managed file system. The INSTANCE_SHARED_DIR keyword can represent either a user-managed file system or a DB2 managed file system. If you create a DB2 managed file system by using the db2cluster_prepare command, you can use the INSTANCE_SHARED_DIR keyword for either a DB2 managed file system or a user-managed file system.

In a DB2 Setup wizard installation, the Set up a DB2 Cluster File System Panel panel detects the cluster environment.

For the db2icrt or db2iupdt command, the -instance_shared_dev option represents a DB2 managed file system. The -instance_shared_dir option can represent either a user-managed file system or a DB2 managed file system. If you create a DB2 managed file system by using the db2cluster_prepare command, you can use the —INSTANCE_SHARED_DIR keyword for either a DB2 managed file system or a user-managed file system, as in the following example:

   db2icrt -d
           -cf host1:host1-ib0
           -m host2:host2-ib0
           -instance_shared_dir mygpfs1
           -tbdev /dev/hdisk2
           -u db2sdfe1
           db2insd1

In this example, the same GPFS cluster is set up on both host1 and host2, and the mygpfs1 file system is mounted on both of them. The mygpfs1 file system is the mount point of the existing GPFS cluster file system. The host names of host1 and host2 must match the host names that are configured on the GPFS cluster. The existing instance owner user, db2insd1, must have write access to the mygpfs1 directory from both host1 and host2. Because a user-managed file system is being used, the -instance_shared_dir parameter is specified rather than the -instance_shared_dev parameter.

When extending the DB2 pureScale instance to a remote host, first extend the cluster to the remote host and set up the host to have write access as root to the file system first. The DB2 installer performs the corresponding validation, as in the following example:

   db2iupdt -d -add -m host3:host3-ib0 db2insd1

In this example, running the command extends the instance to a new member, host3. This host must be included in the same GPFS cluster that has host1 and host2. The mygpfs1 file system must be mounted from host3. The instance owner, db2insd1, must have write access to the mygpfs1 file system.

The DB2 installer and the instance commands do not change the GPFS cluster during the following actions:

The creation of a DB2 pureScale instance
The extension of a DB2 pureScale instance
The dropping of a DB2 pureScale instance
The dropping of a member or cluster caching facility from the instance