Veritas Volume Manager 4.1 Administrator's Guide (HP-UX 11i v3, February 2007)

Chapter 4, Creating and Administering Disk Groups
Handling Conflicting Configuration Copies in a Disk Group
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◆ If the other disks were also imported on another host, no disk can be considered to
have a definitive copy of the configuration database. The figure below illustrates how
this condition can arise for two disks.
Example of a True Serial Split Brain Condition that Cannot Be Resolved Automatically
This is a true serial split brain condition, which VxVM cannot correct automatically. In
this case, the disk group import fails, and the vxdg utility outputs error messages
similar to the following before exiting:
VxVM vxconfigd NOTICE V-5-0-33 Split Brain. da id is 0.1, while dm
id is 0.0 for DM mydg01
VxVM vxdg ERROR V-5-1-587 Disk group newdg: import failed: Serial
Split Brain detected. Run vxsplitlines
The import does not succeed even if you specify the -f flag to vxdg.
Although it is usually possible to resolve this conflict by choosing the version of the
configuration database with the highest valued configuration ID (shown as
config_tid in the output from the vxdg list diskgroup command), this may not be
the correct thing to do in all circumstances.
The following section, “Correcting Conflicting Configuration Information,” describes
how to fix this condition.
Disk A
Actual A = 1
Expected A = 1
Expected B = 0
Configuration
Database
Disk B
Actual B = 1
Expected A = 0
Expected B = 1
Configuration
Database
Shared Disk Group Fails To Import
Disk A
Actual A = 1
Expected A = 1
Expected B = 0
Configuration
Database
Disk B
Actual B = 1
Expected A = 0
Expected B = 1
Configuration
Database
Partial Disk Group
Imported on Host X
Partial Disk Group
Imported on Host Y
1.Disks A and B are imported
independently on separate
hosts. The actual and
expected serial IDs are
updated independently on
each disk.
2.The disk group cannot be
reimported on the cluster.
This is because the
databases do not agree on
the actual and expected
serial IDs. You must choose
which configuration
database to use.