Migrating and Moving Data

ISMF uses both DFSMShsm and DFSMSdss commands to help you perform these tasks:

Migrate less active data sets from primary storage to other devices (like or unlike).
Recall data sets when you need them again.
Move data sets to DASD volumes of like or unlike device types.

Table 1 summarizes the DFSMShsm and DFSMSdss commands that ISMF uses for migration and data movement.

Table 1. Summary of Commands to Migrate and Move or Copy Data Sets
Task	Function	Scope	Action
Move or copy less active data sets from primary storage to other devices (like or unlike).	HMIGRATE	Single data set	Migrates a data set to a DFSMShsm level 1 or level 2 volume. Performed in the foreground by DFSMShsm.
Recall data sets that have been migrated by DFSMShsm.	HRECALL	Single data set	Recalls a single data set that has been migrated by DFSMShsm. Performed in the foreground by DFSMShsm.
Move or copy data sets to DASD volumes of like or unlike device type.	COPY	Single data set, group of data sets, or volume	Copies data sets to DASD volumes of like or unlike device type. Performed in the background by DFSMSdss.

Using DFSMShsm for Migration of Data

When DFSMShsm migrates data, it uses a hierarchy of storage devices that have different costs for storing data and different speeds of accessing the data. Less active data is stored further down in the hierarchy. The hierarchy consists of three levels of devices and volumes:

Level 0: Storage devices that contain data directly accessible to you. Level 0 volumes are always mounted and online.
Level 1: Storage devices that contain data compressed by DFSMShsm. These devices may provide cheaper storage, but the access time is usually slower. Level 1 volumes contain data sets that DFSMShsm has moved from level 0 volumes. They are usually permanently mounted and online.
Level 2: Storage devices that contain data compressed by DFSMShsm. Like level 1, these devices may provide cheaper storage, but the access time is usually slower. Level 2 volumes contain data sets that DFSMShsm has moved from level 1 or level 0 volumes. They are normally not mounted or online.

Both migration and recall are usually performed automatically by DFSMShsm space maintenance. However, you can choose to perform space maintenance yourself. For example, if you know that certain data sets will not be used for some time, you can migrate them immediately. You might also need to recall a data set before DFSMShsm is scheduled to do so. With the HMIGRATE and HRECALL line operators you can manually make use of the DFSMShsm storage hierarchy.

HMIGRATE allows you to migrate individual data sets to level 1 or level 2 volumes. When you enter HMIGRATE in the line operator column of the data set you want to move, ISMF displays the HMIGRATE Entry Panel. On the data entry panel, you can specify the migration level you want DFSMShsm to use and the password if the data set is password-protected. Because HMIGRATE is performed in the foreground, you can choose to wait for completion. If you choose to wait, ISMF displays the HMIGRATE Entry Panel until the data set has been migrated. When the HMIGRATE is completed, the list panel is displayed again.

HRECALL recalls individualdata sets that have been migrated to level 1 or level 2 volumes. On the HRECALL Entry Panel, you can direct the recall by specifying the volume serial number and device type for DFSMShsm to use. If you do not choose a specific volume and device type, DFSMShsm chooses a volume for the recall. Like HMIGRATE, the HRECALL line operator is performed in the foreground. You have the option of returning to the list panel immediately or waiting for the data set to be recalled before continuing.

Using COPY as a Device Migration Aid

With COPY you can copy or move a single data set, a group of data sets, or a volume to a DASD volume of like or unlike device type. For example, you can use COPY to move data sets from a 3380 to a 3390 or from one model 3390 to another. COPY is a valuable tool for device conversion.

When you enter the COPY line operator or list command, ISMF displays the data entry panel for COPY. On the COPY Entry Panel, you can specify the following options:

Delete the original data sets after they have been copied.
Rename the data sets as they are copied.
Control the replacement of duplicate copies of data sets.
Reblock sequential or partitioned data sets.
Specify where to catalog the new data set.
Specify the volume to receive the new data set and how much space to allocate on the volume.
Provide the name of a RACF® model data set to use to define the RACF profile for the new data set.
Specify a maximum number of attempts DFSMSdss should make to serialize the data set and the number of seconds between each retry.
Copy the data set even if it is being used by another program.
Copy data sets that were allocated as unmovable.
Use dynamic allocation instead of enqueue to serialize the use of the data set.
Allow other programs read access to the data sets while the data sets are being copied.
Copy all allocated space or only space that has actually been used.
Verify the data after the COPY.
Stop the COPY after the first I/O error or after 100 errors.
Copy basic direct access method (BDAM) data set by relative block or TTR.

If you are performing a task against a volume, you also have the following options:

Specify a logical or physical copy.
Copy multivolume data sets.

The online help describes how to complete each field on the COPY Entry Panel. Defaults are provided for many of the options.