HP StorageWorks Storage Mirroring user's guide (T2558-96073, February 2008)
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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.
Full qualified domain name of the source—Alpha.domain.com
Source IP address—192.168.1.108
Fully qualified domain name of the target—Beta.domain.com
Target IP address—116.123.2.47
Fully qualified domain name of the DNS server—DNSServer.domain.com
DNS zone—domain.com
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.