Setting up an IBM Storage Scale file system for a Db2 pureScale environment

To set up an IBM Storage Scale file system for a Db2 pureScale environment, you can create a new IBM Storage Scale file system, use an existing user managed IBM Storage Scale file system, or have Db2 cluster services take control of an existing IBM Storage Scale file system.

Before you begin

Note: db2cluster is for AIX and db2cm is for Linux. Change any commands or command outputs as needed by your Operating System.

Review the information in Planning to convert your environment to a Db2 pureScale environment.
Ensure that you have root access to use the db2cluster_prepare command.
When using a User-Managed Storage Scale file system, the pureScale installation must match the topology of the underlying file system. A CF or member must be installed on each GPFS node.

About this task

In a Db2 pureScale environment, all data and logs must be on IBM Storage Scale file systems.

If you have an existing Db2 database, run the db2checkSD command as detailed in Verifying that your databases are ready for a Db2 pureScale environment. If any table spaces that are not managed by automatic storage, or that are not on an IBM Storage Scale file system are reported, you must convert the table spaces and move the data to IBM Storage Scale file systems before conversion. Before moving the data, you might need to create a Db2 managed IBM Storage Scale cluster and file system, or verify that an existing IBM Storage Scale cluster and file system can be used by Db2 as a user managed IBM Storage Scale.

Procedure

To configure an IBM Storage Scale file system for a Db2 pureScale environment, based on your environment, choose one of the following options:

Option Description

Option	Description
No existing IBM Storage Scale cluster	Set up a new Db2 cluster file system on a host that does not have an existing IBM Storage Scale cluster. This is the recommended method to set up a Db2 pureScale environment. With root access, use the db2cluster_prepare command to create a Db2 managed IBM Storage Scale file system. For example: `db2cluster_prepare -instance_shared_dev /dev/hdisk1` Verify the mount location. To list the file systems, run the following db2cm command on Linux systems. For example: `db2cm -cfs -list -filesystem` On AIX systems, run the following db2cluster command: `db2cluster -cfs -list -filesystem`
Takeover of existing user managed IBM Storage Scale cluster	Use an existing user managed IBM Storage Scale cluster and have Db2 cluster services take over the management of the cluster. With root access, run the db2cluster_prepare command with the -cfs_takeover option to have Db2 cluster services manage an existing IBM Storage Scale cluster. `db2cluster_prepare -cfs_takeover`
Use an existing user managed IBM Storage Scale cluster	Identify and continue using an existing user managed IBM Storage Scale cluster. Perform these steps to use an existing IBM Storage Scale as a user managed file system. The Db2 pureScale Feature can use a user managed IBM Storage Scale cluster and file system, but when the Db2 installer and instance utilities are used to extend a Db2 pureScale instance that has a user managed IBM Storage Scale cluster and file system, the host must be added to the IBM Storage Scale cluster manually and the related file systems on the host must be mounted manually. Similarly, when the Db2 installer and instance utilities are used to shrink a Db2 pureScale instance that has a user managed IBM Storage Scale cluster and file system, the host must be removed from the IBM Storage Scale cluster manually and the related file systems on the host must be unmounted manually. When the IBM Storage Scale cluster and file system are Db2 managed, the Db2 installer and instance utilities will add or remove the host and issue the required mount or unmount commands when the host is added to or removed from the Db2 pureScale instance. For more information about the additional steps required to add a member or cluster caching facility when IBM Storage Scale is user managed, see the User-managed file system topic. Before using an existing IBM Storage Scale, you must verify that IBM Storage Scale is set up correctly: On AIX systems, run the db2cluster command from the /bin directory with the following options: `db2cluster -cfs -verify -configuration -filesystem filesystem-name` Verify the file system. You must perform this step for each file system that you plan to use with Db2 pureScale Feature. For example, run the db2cm command from the <DB2InstallPath>/bin directory with the following options: `db2cm -cfs -verify -configuration -filesystem filesystem-name`

No existing IBM Storage Scale cluster

Set up a new Db2 cluster file system on a host that does not have an existing IBM Storage Scale cluster. This is the recommended method to set up a Db2 pureScale environment.

With root access, use the db2cluster_prepare command to create a Db2 managed IBM Storage Scale file system. For example:
```
db2cluster_prepare -instance_shared_dev /dev/hdisk1
```
Verify the mount location. To list the file systems, run the following db2cm command on Linux systems. For example:
```
db2cm -cfs -list -filesystem
```

On AIX systems, run the following db2cluster command:

db2cluster -cfs -list -filesystem

Takeover of existing user managed IBM Storage Scale cluster

Use an existing user managed IBM Storage Scale cluster and have Db2 cluster services take over the management of the cluster. With root access, run the db2cluster_prepare command with the -cfs_takeover option to have Db2 cluster services manage an existing IBM Storage Scale cluster.

db2cluster_prepare -cfs_takeover

Use an existing user managed IBM Storage Scale cluster

Identify and continue using an existing user managed IBM Storage Scale cluster.

Perform these steps to use an existing IBM Storage Scale as a user managed file system. The Db2 pureScale Feature can use a user managed IBM Storage Scale cluster and file system, but when the Db2 installer and instance utilities are used to extend a Db2 pureScale instance that has a user managed IBM Storage Scale cluster and file system, the host must be added to the IBM Storage Scale cluster manually and the related file systems on the host must be mounted manually. Similarly, when the Db2 installer and instance utilities are used to shrink a Db2 pureScale instance that has a user managed IBM Storage Scale cluster and file system, the host must be removed from the IBM Storage Scale cluster manually and the related file systems on the host must be unmounted manually. When the IBM Storage Scale cluster and file system are Db2 managed, the Db2 installer and instance utilities will add or remove the host and issue the required mount or unmount commands when the host is added to or removed from the Db2 pureScale instance. For more information about the additional steps required to add a member or cluster caching facility when IBM Storage Scale is user managed, see the User-managed file system topic.

Before using an existing IBM Storage Scale, you must verify that IBM Storage Scale is set up correctly:

On AIX systems, run the db2cluster command from the /bin directory with the following options:
```
db2cluster -cfs -verify -configuration -filesystem filesystem-name
```
Verify the file system. You must perform this step for each file system that you plan to use with Db2 pureScale Feature. For example, run the db2cm command from the <DB2InstallPath>/bin directory with the following options:
```
db2cm -cfs -verify -configuration -filesystem filesystem-name
```

What to do next

Convert your table spaces for a Db2 pureScale environment.