Hostname for Standby Database

Question

Hi All,
We are setting up standby database for MSSQL2008 in windows 2008 R2 environment. For our customer scenario, their infra team insist of using log shipping to transfer log file and file replication to to replication SAP files.
Therefore, i've a question in mind.. Do we need to maintain identical hostname for primary and standby database? fyi, they have cluster their primary and DR host.
If different hostname, virtual hostname is used, basically we can just drop the primary host from the domain and change that respective hostname, virutal hostname and ip for the DR host during swing over? If that's the case, is the any other action we need to perform? Do we need to change any registry? I believe SAP profiles and etc are identical due to the file replication.
If same hostname is maintained for both primary and standby host, i believe we might need to isolate standby host from the network and change the entries in DNS or routing table during swing over?
Any feedback and good suggestion are mostly welcome and much appreciate.
Cheers,
Regards
Nicholas Chang.
Edited by: Nicholas Chang on Feb 10, 2011 4:36 PM
Edited by: Nicholas Chang on Feb 10, 2011 4:37 PM

Answer 1

Hi,
when the primary and the standby database server are on the same network, they have to have a different hostname.
Is the SAP Ci on the same Cluster as the DB (active-active Cluster) ?
Is the SAP System itself a cluster ?
You have three different scenarios here:
- only the DB cluster is failing
- only the CI Cluster/System is failing
- both systems are failing
For the first case you can
- either change the profiles of the primary SAP system to point to the new DR DB Host
- or define a AD alias in beforehand, to which you connect normally.
   Then you have to change the alias only to point the SAP System to the new DR DB Host
For the second case you can
- change the profiles of the DR SAP System to point to the primary DB Host
- or define a AD alias in beforehand, to which you connect normally. When you start
  the DR SAP Systen then, it will connect to the primary DB Host
For the third case you can
- change the profiles of the DR SAP System to point to the seondary DB Host
- or define a AD alias in beforehand, to which you connect normally.
  In the DR case you have to change the Alias in the AD and then you can
  start the DR SAP Systen. It will connect to the primary DB Host
Changing the virtual or physical hostname during DR swing over is not a good option,
as you have too many side effects. Using an Alias is much easier and faster.
Using Database Mirroring (SQL 2005 or higher) will eliminate case 1, as the SAP
system can swing over to the DR side automatically in the DR case.
Best regards
  Clas