Systems support can use the RESTORE-PUBSET-FROM-SNAPSET command to restore the entire pubset from an existing Snapset of the pubset on a volume basis. This function cannot be executed in active pubset mode. The pubset must be exported, i.e. it may not have been imported into another system either locally or remotely. It must also still exist on the original disks and have the original pubset attributes (see also section “Changing the pubset configuration” in chapter "Saving using Snapsets").
In the storage system, the pubset is restored to the status of the relevant Snapset. The pubset then has the same status as immediately before this Snapset was generated.
The pubset is protected against being placed in service by /IMPORT-PUBSET until the restore operation has been concluded.
While restoration is in progress, a temporary copy of the Snapset catalog of the pubset which is to be restored is created on the home pubset and assigned the file name $TSOS.SYSWRK.SNAPSET.<catid>. This file is only required for restoration and is only deleted once restoration has been completed. While restoration is in progress it is protected against being deleted because it is used for restarting an interrupted restore operation (see below). If the pubset is restored in another way, the file is deleted when the next pubset import takes place.
After a session is aborted while restoration is in progress, the pubset is in an intermediate status which corresponds to a partial restoration. In this case restoration can be completed by issuing the command again. However, restoration can only be started again in the same runtime environment, i.e. with the same home pubset, because the copy of the home pubset which is required is located there.
With ETERNUS DX/AF systems reconstruction of a pubset can be executed on any Snapset of that pubset. All these Snapsets including that one used for reconstruction, are retained and can continue to be used.
Note on the SNAPSET operand of the RESTORE-PUBSET-FROM-SNAPSET command
SNAPSET = *LATEST
While the function is being executed, the pubset is not implicitly imported. F5 label restoration takes place when the restored pubset is imported.SNAPSET = <name 1..1 with-low> / <integer -52..-1> (explicit entry)
While the function is executed, the pubset is implicitly imported and at the end exported again. In this case F5 label restoration also takes place implicitly.
Changing the pubset configuration
When the pubset has been reduced by the removal of disks following the last Snapset save and these disks have been reinitialized using VOLIN, it is no longer possible to restore the pubset. In this case the RESTORE-PUBSET-FROM-SNAPSET command is rejected.
The option of restoring the pubset following a pubset reduction can be retained by means of one of the following measures:
Do not reinitialize removed disks
Generate a new Snapset immediately
VOLIN does not permit snap units to be initialized and responds to the initialization of original disks by inquiring if snap units are still concatenated.