Distributed Name Service (DNS) Management Operations Manual

Backing up the DNS Configuration
DNS Management and Operations
3–12 31258 Tandem Computers Incorporated
Backing up the DNS
Configuration
To back up your DNS configuration files, do one of the following steps right after
initializing a DNS configuration:
Use the SYSGEN program to copy the DNS configuration files to your system
image tape.
Back up the DNS configuration file onto magnetic tape with the BACKUP
program described in the BACKUP/RESTORE section of the Guardian 90
Operating System Utilities Reference Manual.
In addition, it is a good habit to always have a backup for your DNS database. In as
much as DNS database files are audited using TMF, the TMFCOM DUMP FILES
command is the recommended method to backing up the DNS database files. As with
the DNS configuration files, you can use the BACKUP program to back up the DNS
database.
Recreating a
Configuration File
If you lose a DNS configuration file, the usual way to recreate it is to use the
INITIALIZE DNS, DNSCONFONLY command.
Alternatively, you may want to provide a backup of your DNS configuration files; see
the “Backing up the DNS Configuration,” in this section.
Updating Definitions
on Unavailable Nodes
When the definition node for a set of names fails (or becomes unavailable for any
other reason), this failure removes the point of control that DNS would otherwise use
for altering the definitions of those names. The definition node is the node where the
original name was defined and where the definition resides. In this case, when
someone attempts to alter one of those names from another node, this attempt fails.
If a name’s definition node is unavailable but you still want to update the name’s
definition immediately, you can ask DNS to provide an alterable copy of that
definition on your own node with the COPY command:
COPY name
Once this copied name definition is provided, you are free to alter it in any way.
However, your changes to the copied name definition affect only your local node’s
view of the name.
When the definition node becomes available, you can resynchronize the name as
defined throughout the network by asking DNS to restore the name with the
RESTORE command:
RESTORE name
This action deletes the copied definition and makes the definition node’s version (now
called the restored name definition) visible once again at your node.
If the definition node’s version was altered after that node became available, but
before your restore request, the restored name definition will differ from the definition
that you originally copied.