Activating clone pairs

This function is only necessary for EC and TimeFinder/Clone.
Clone pairs created and managed with QuickOPC will be activated automatically after their creation.

In order to use clone units, the clone pairs must be activated in a clone session using /ACTIVATE-CLONE. For Symmetrix/VMAX3 the clone pair must be in the status CREATED, RECREATED or PRECOPY, and for ETERNUS DX/AF in the SYNCHRONIZED status. For Symmetrix/VMAX3 the unit and clone unit do not need to be synchronous; activation can consequently take place immediately after the clone session has been created.

Following successful activation, the unit and the clone unit are split, i.e. both can be accessed by the server for applications. The clone unit contains all the data which was on the unit at the time the command was processed.

The clone pairs which are activated can be selected in different ways: via their VSN, their mnemonic name, their internal number in the storage system, or the ID of the pubset or volume set to which they belong. The most frequent method is selection via the pubset ID, which enables all clone pairs of this pubset to be activated. This method is described below.

Entire pubset

All clone pairs in a pubset are activated using the following command:
/ACTIVATE-CLONE UNIT=*BY-PUBSET(PUBSET=<cat-id>,...),...

A synchronization point for the data must be created beforehand:

• suspend or terminate applications

• close all files or

• export the pubset.
  Only with an exported pubset is it ensured that all data buffered using DAB will be written back from the cache (database etc.).

If you do not export the pubset, note the following:

• Write caching using DAB at server level must be terminated:

  • PFA caching: /STOP-PUBSET-CACHING

  • ADM-PFA caching: /STOP-DAB-CACHING

• If the pubset consists of more than one unit, the input and output processes should be suspended during splitting: /ACTIVATE-CLONE command with the UNIT=*BY-PUBSET and HOLD-IO=*UNTIL-ACTIVATED operands.

• During import, the split pubset on the clone units behaves as if the last export procedure had not been executed. Consequently either the message DMS038C must be answered with Y or the SESSION-CHECK-MSG=*NO operand must be specified in /IMPORT-PUBSET. The F5 labels on the volumes are reconstructed from the catalog.

  Files on the split pubset are in the same status as on the original pubset at the time splitting took place; they may possibly not have been closed. In this case the /REPAIR-DISK-FILES command is required if this is not executed automatically by the application (same effect as restart capability after system failure).

For details of the commands mentioned, please refer to the “Commands” manual [1].

If the split pubsets are processed in the same BS2000 session as the originals, they must be renamed. Note the following:

• The clone units must be (generated and) attached.

• SF pubsets can be renamed directly using /ACTIVATE-CLONE with the NEW-PUBSET=<new cat id> operand. The new pubset ID can also be shorter than the old pubset ID.

• IMON uses the SYS.IMON.SCI file, which contains pubset IDs. If the SCI file is located on the pubset which is split and renamed, when renaming takes place using /ACTIVATE-CLONE it must be modified manually using /MODIFY-IMON-SCI (see the “IMON” manual [11]). The PVSREN program does this automatically.

• SF pubsets can also be renamed automatically using /ACTIVATE-CLONE with the NEW-PUBSET=*SPECIAL-VSN operand in order to prevent confusion with the original. The period in a VSN is changed to a colon; in the case of single-digit catalog IDs, the “PUB” string is changed to “P:B”. Backups using the software product FDDRL are then performed using the original VSN and can be restored under the original VSN. For information on FDDRL (Fast Disk Dump and ReLoad) see the “FDDRL” manual [9].

• When HSMS (see the “HSMS” manual [10]) is used, TimeFinder/Clone only duplicates the S0 level (normal processing level) of the pubset; migrated files consequently exist once only on the tape and in the HSMS directory.

  CAUTION!
  No files may be migrated or restored on the additional mirror pubset. Otherwise data can be lost.

• Paging files are renamed automatically. If pubset IDs or VSNs have been programmed into the applications, these must be adjusted manually.

• The PVSREN program can complete renaming operations performed by SHC-OSD for IMON, SYSID and the default pubset for user IDs.

• If a system is to be started from the clone unit, the SYSID must be changed beforehand using /SET-PUBSET-ATTRIBUTES (see the “Commands” manuals [1]).

  A unique SYSID is required in MSCF environments!

If the pubset is not renamed, the clone units cannot be used in the same system because they have the same VSN. They can, however, be used by another server or a virtual machine.

Private disks

The following special aspects must be borne in mind for clone pairs on private disks:

• Private disks cannot be renamed.

• The applications must be terminated.

• The HOLD-IO operand is not supported.

• Private disks must be released using /SET-DISK-PARAMETER with the ASSIGN-TIME=*USER operand.

Further sequence of operations

/UNLOCK-DISK is executed internally for all clone units (see the “Commands” manuals [1]) provided these are attached.

Console message NDE0060 indicates that the activation process has been completed. After the split process has been completed, the status can also be displayed using /SHOW-CLONE-SESSION-STATUS.

When all clone units of a pubset have been activated, the clone pubset can be imported as soon as the split process has been completed and the COPY-ON-ACCESS, COPY-IN-PROG or COPIED status has been assumed for Symmetrix/VMAX3 or the SPLIT status for ETERNUS DX/AF. The associated MRSCAT entry is automatically created or updated.

Consistent splitting of a pubset in the shared pubset network

Requirements

• No DAB write caching may be active.

• All sharers have SHC-OSD V13.0 or higher started.

• The command is executed on the master.

• There must be MSCF connections between the master and all sharers.

• The pubset may not have the QUIET status.

/ACTIVATE-SNAP with the UNIT=*BY-PUBSET(...,HOLD-IO=*UNTIL-ACTIVATED) operand enables clone activation at a synchronization point during ongoing operation without exporting the pubset. Shared pubsets with multiple sharers in a CCS network can also be split consistently. This function interrupts all outputs to the pubset during splitting. It is therefore possible, for example, to create a consistent copy of the home pubset during ongoing operation and to back it up or use it in parallel as a standby pubset.

CAUTION!
/RESUME-IO can be used to resume suspended input/output activity for pubsets.
This command is provided for emergencies only and if used without due care may endanger data consistency on the split clone units.