Pubset reconfiguration

Configuration data and also the disk and volume set configuration of a pubset can be modified via command interfaces of the pubset reconfiguration in BS2000 during pubset operation (dynamic pubset reconfiguration). Basic information on this is provided in the section “Dynamic pubset reconfiguration” in the “Introduction to System Administration” [2].

Pubset reconfiguration is executed by the guest system for the pubsets which are assigned exclusively to it. For shared pubsets, pubset reconfiguration is initiated by any guest system and executed for all slave sharers under the control of the pubset master.

• VM2000 is informed if the system support of a guest system uses the BS2000 command /MODIFY-PUBSET-PROCESSING during ongoing operation to add (*ADD) or remove (*REMOVE) volumes to/from a pubset which is assigned to the VM.

• When a pubset is attached in the guest system using /ATTACH-DEVICE UNIT=*PUBSET-DEVICES(...) in a guest system, VM2000 detects a pubset reconfiguration which was performed by another system. However, only the adding of volumes (*ADD) is detected.

In both cases VM2000 adjusts the assignment mode (explicit, implicit), the usage mode (exclusive, shareable) and the device attributes (ASSIGN-BY-GUEST attribute) for the pubset devices if necessary, see paragraph "Adjustments by VM2000". In special cases, manual adjustments by the VM2000 administrator may be required, see paragraph "Manual adjustments by the VM2000 administrator".

The modified pubset configuration is automatically taken into account in the next VM2000 command which addresses the pubset.

Adjustments by VM2000 when a new pubset device is detected

In the following cases VM2000 implements any adjustments which are required:

• The systems support of a guest system uses the BS2000 command /MODIFY-PUBSET-PROCESSING during ongoing operation to add a new volume (*ADD) to a pubset which is assigned to the VM.

  In the case of a shared pubset, VM2000 implements the adjustments on the Server Unit for all the guest systems involved, provided at least one of these guest systems is running.

• The systems support of a guest system uses /ATTACH-DEVICE UNIT=*PUBSET-DEVICES(...) to attach a pubset to which new volumes were added from another system beforehand.

• The systems support of a guest system uses /ATTACH-DEVICE UNIT=*PUBSET-DEVICES(...) to attach a pubset whose pubset devices could not (yet) be found by VM2000 during the preceding explicit pubset assignment.

If the pubset is explicitly assigned to the VM, i.e. the pubres device has assumed the PUBRES-FOR-ASSIGNMENT attribute for the VM, and the new pubset device is not assigned to the VM explicitly, VM2000 implements the following adjustments:

• If the pubres device has the usage mode SHARED, the new pubset device is assigned explicitly to the VM and assumes the usage mode SHARED.

• If the pubres device has the usage mode EXCLUSIVE and the new pubset device does not have the usage mode SH(I), the new pubset device is assigned explicitly to the VM and assumes the usage mode EXCLUSIVE.

If the pubres device and the new pubset device are assigned implicitly to the VM, VM2000 implements the following adjustments:

• If the pubres device has the usage mode SHARED, the new pubset device assumes the usage mode SHARED.

• If the pubres device has the usage mode EXCLUSIVE and the new pubset device does not have the usage mode SH(I), the new pubset device assumes the usage mode EXCLUSIVE.

If the device attribute ASSIGN-BY-GUEST was assigned for the pubset, i.e. the pubres device has the PUBRES-FOR-ATTRIBUTES attribute, or if the default value for the VM2000 parameter ASSIGN-BY-GUEST (see "MODIFY-VM-DEVICE-ATTRIBUTES (Modify device attributes)") applies for the device attribute of the pubres device, the new pubset device assumes the same device attribute as the pubres device.

Adjustments by VM2000 when a pubset device is removed

If the systems support of a guest system uses the BS2000 command /MODIFY-PUBSET-PROCESSING during ongoing operation to remove a volume (*REMOVE) from a pubset which is assigned to the VM, VM2000 implements the following adjustments, as required:

• If the pubset is assigned explicitly to the VM, i.e. the pubres device has the PUBRES-FOR-ASSIGNMENT attribute for the VM, the remote device assumes the assignment mode implicitly.

• If the remote device had the usage mode EXCLUSIVE, it assumes the usage mode SH(D).

In the case of a shared pubset, VM2000 implements the adjustments on the Server Unit for all the guest systems involved.

Manual adjustments by the VM2000 administrator

Manual adjustments by the VM2000 administrator are still required in multisystem operation for the special cases listed below as the usage and assignment modes for a device and VM cannot be adjusted by VM2000:

• If the pubset is assigned explicitly to an active VM but is not imported in the guest system and in this state a volume is removed from the pubset by a system on another Server Unit using /MODIFY-PUBSET-PROCESSING.

• If the home pubset is assigned explicitly to a VM in the DOWN state and in this state volumes are added to or removed from the home pubset by another system using /MODIFY-PUBSET-PROCESSING.