HP Storage Mirroring V5.1 Software - Manual (Page 116)

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DNS
When Storage Mirroring failover occurs, DNS is not automatically updated. If the end-users use DNS
to resolve server names and the source IP address was not failed over to the target, additional DNS
updates will be required because the host records for the source will remain intact after failover. You
can automate this process by scripting the DNS updates in the failover and failback scripts. You have
two options for scripting the DNS updates.

Windows DNSCMD command—The Windows Support Tools contain a DNS Server
Troubleshooting Tool utility. This utility includes the DNSCMD command which can be scripted to
delete and add host and reverse lookup entries in DNS.

Storage Mirroring DFO command—Storage Mirroring also has a utility, called the DFO (DNS
Failover). The DFO command can be used to script the deletion and addition of the host and
reverse lookup entries in DNS. This utility can be found on the product CD or from the HP support
web site.
Windows DNSCMD command
DNS updates can be added to your failover and failback scripts by using the Windows DNSCMD
command as long as dynamic updates are enabled on the DNS zone and the account running the
Storage Mirroring service is a member of the DNSAdmins security group. (See your Microsoft
documentation to verify if dynamic updates are enabled.) Add the following commands to your
failover and failback scripts to delete the host and reverse lookup entries and add new entries
associating the source to the target.
dnscmd DNS_server’s_FQDN /RecordDelete DNS_zone source_server_name A
source_server_IP_address /f
dnscmd DNS_server’s_FQDN /RecordDelete www.xxx .in-addr.arpa zzz.yyy PTR
source_server’s_FQDN /f
dnscmd DNS_server’s_FQDN /RecordAdd DNS_zone source_server_name A
target_server_IP_address
dnscmd DNS_server’s_FQDN /RecordAdd aaa.bbb .in-addr.arpa ddd.ccc PTR
source_server’s_FQDN
The variables used in the commands are defined in the table below.
For example, suppose you had the following environment.
Variable Description
DNS_servers’s_FQDM The fully qualified domain name of the DNS server
DNS_zone The name of the DNS zone
source_server_name The name of the source server
source_server_IP_address The IP address on the source
www.xxx The first two octets of the source’s IP address. For example, if the
source’s IP address is 192.168.1.108, this variable would be
192.168.
zzz.yyy The last two octets, in reverse order, of the source’s IP address.
For example, if the source’s IP address is 192.168.1.108, this
variable would be 108.1.
source_server’s_FQDN The fully qualified domain name of the source server
target_server_IP_address The IP address on the source
aaa.bbb The first two octets of the target’s IP address. For example, if the
target’s IP address is 116.123.2.47, this variable would be
116.123.
ddd.ccc The last two octets, in reverse order, of the target’s IP address.
For example, if the target’s IP address is 116.123.2.47, this
variable would be 47.2.