Mounting a Shadow
Set on Other Nodes in the Cluster
If a shadow set is already mounted on one or more nodes in
an OpenVMS Cluster system, the /SHADOW qualifier is not required
when you mount the same shadow set on other nodes in the cluster.
For example, if DSA42 is already mounted in the cluster when a new
node is brought into the cluster, you can use the following command
to mount DSA42 on the new node:
$ MOUNT/SYS DSA42: volume-labellogical-name
Upon receiving this command, the volume shadowing software
creates the shadow set on the new node with the same members that
currently exist on other nodes in the cluster.
Reconstructing a Shadow Set With /INCLUDE Reconstructing Shadow Sets With /INCLUDE shows
how to reconstruct a shadow set. The volume shadowing software determines
which disk volumes are former members of the shadow set.
Example 8 Reconstructing Shadow Sets With /INCLUDE
$ MOUNT /SYSTEM DSA4/SHAD=($4$DIA1,$4$DIA2,$4$DIA3) NEWDISK
%MOUNT-I-MOUNTED, NEWDISK mounted on _DSA4: %MOUNT-I-SHDWMEMSUCC, _$4$DIA1: (DISK01) is now a valid member of the shadow set %MOUNT-I-SHDWMEMCOPY, _$4$DIA2: (DISK02) added to the shadow set with a copy operation %MOUNT-I-SHDWMEMCOPY, _$4$DIA3: (DISK03) added to the shadow set with a copy operation $ DISMOUNT DSA4
$ $ MOUNT DSA4:/SYSTEM/SHAD=$4$DIA1 NEWDISK/INCLUDE
%MOUNT-I-MOUNTED, NEWDISK mounted on _DSA4: %MOUNT-I-SHDWMEMSUCC, _$4$DIA1: (DISK01) is now a valid memberof the shadow set %MOUNT-I-AUTOMEMCOPY, _$4$DIA2: (DISK02) automatically addedto the shadow set %MOUNT-I-AUTOMEMCOPY, _$4$DIA3: (DISK03) automatically added to the shadow set
The first command in this example creates the shadow set represented
by DSA4. The shadow set consists of three shadow set members: $4$DIA1,
$4$DIA2, and $4$DIA3.
After all copy operations have completed, the DISMOUNT command
dissolves the shadow set.
The /INCLUDE qualifier shown in the second MOUNT command triggers
the MOUNT command to reconstruct the shadow set back to the way
it was before the shadow set was dissolved. The MOUNT command must
specify the original virtual unit name (DSA4) and at least one of
the original shadow set members ($4$DIA1). The Mount utility reads
the membership list on $4$DIA1 (specified in the first MOUNT command)
to determine that $4$DIA2 and $4$DIA3 are also members of the shadow
set.
Because the shadow set was properly dismounted, the shadow
set members are in a consistent state. The MOUNT status messages
indicate that the shadow set devices are added back into the shadow
set without the need for copy operations.
Mounting a Former Shadow Set Member as a
Nonshadowed Disk Occasionally, you will need to mount a physical shadow set
member as a nonshadowed disk. By default, when a shadow set member
is mounted outside a shadow set, the Mount utility automatically
write-locks the disk. This provides a safeguard against accidental
modification, thereby allowing the disk to be remounted into a shadow
set at a later time.