Placing Your Volumes under System Management

Each of your DASD volumes is either system-managed or non-system-managed. A data set on DASD is system-managed when it satisfies the following requirements:

It has a valid SMS storage class assigned.
It resides on a volume in an SMS storage group that has been initialized as a system-managed volume or has been migrated to system management.

The value of SMS VOLUME STATUS shows the relationship of the volume to SMS. Your volumes can assume three states:

Converted

Indicates that the volume is fully available for system management. All data sets on the volume have a storage class and are cataloged in an integrated catalog facility catalog.

Initial

Indicates that the volume is not fully available for system management because it contains data sets that are ineligible for system management.

An attempt was made to place the volume under system management, but data sets were determined to be ineligible for system management based either on SMS eligibility rules or on the decisions made in your ACS routines. Temporary failure to migrate to system management occurs when data sets are unavailable (in use by another application) when the migration is attempted.

No new data set allocations can occur on a volume with initial status. Also, existing data sets cannot be extended to another volume while the volume is in this state.

You can place volumes in initial status as you prepare to implement system management.

Tip: You can use the DFSMSdss CONVERTV function with the TEST option to determine if your volumes and data sets are eligible for system management. See Testing the Eligibility of Your Volumes and Data Sets for more information on the TEST option.

Non-SMS

The volume does not contain any system-managed data sets and has not been initialized as system-managed.

You can either do data conversion with movement using DFSMSdss's COPY or DUMP/RESTORE functions, or you can convert in-place using DFSMSdss's CONVERTV function. The approach you use to place your data under system management depends on the following considerations:

The degree of centralization of the storage management function
If most of your data resides in centrally-managed storage pools, you might be able to use the in-place conversion approach. TSO and database data might be migrated using this technique, because these data categories are likely to have similar management characteristics and reside in storage pools.

In contrast, if your storage is mainly application-owned, you must do data conversion with movement. Also, batch application data requires data movement, because this data has more diverse management requirements and is less likely to be pooled. For this data category, implementing system management on an application-by-application basis is most appropriate.
Your inventory of available DASD volumes
If few volumes are available for new allocation, you can use in-place conversion for the initial migration.
The eligibility of your data to be system-managed
For example, data sets that are unmovable or ISAM cannot be system-managed. Eligible data sets that coexist on these volumes must be moved to system-managed volumes.
The availability of your data sets
The in-place conversion technique requires exclusive use of the data sets on the volumes to be migrated. You should do this during off-peak hours.
The ability of your storage configuration hardware to deliver target performance and availability services
Use the conversion with data movement approach if:
- Your storage hardware configuration has cached and non-cached storage controls, to achieve better performance and greater automation of performance management.
- You plan to use sequential data striping.
- You plan to use point-in-time copy, to ensure that data sets requiring high-performance backup are placed on volumes attached to cache-capable 3990 storage controls with the extended functions, or behind the RAMAC Virtual Array with the SnapShot feature and the DFSMSdss virtual concurrent copy SPE installed.
- You plan to use dual copy, to place the data sets on volumes attached to cache-capable 3990 storage controls with the extended functions.

One benefit of doing conversion with data movement is that the data is allocated according to the allocation thresholds that you set for the storage groups, so that space usage can be balanced.

Tip: When doing conversions-in-place, consider that the ACS variables available to your routines are more limited when using the DFSMSdss CONVERTV function. For more information, see the DFSMSdss section of z/OS DFSMSdfp Storage Administration.