HP StorageWorks Storage Mirroring application notes Guidelines for networking and failover (T2558-96063, February 2008)

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After Failover
Additionally,
nbtstat -a [target IP address] can be run from a remote system to show the target's
name table to retrieve the same information.
The
ipconfig command can be used to verify that the source's IP address has failed over to the target.
Failed-over IP addresses will be listed in the ipconfig output as well as in the network adapter's TCP/IP
Properties Advanced dialog box.
Replace option
Storage Mirroring includes a replace option that enables the target to replace its computer name and IP
address with the source's computer name and IP address at failover. This option is supported on Windows
NT 4.0 targets in the released versions of Storage Mirroring, and in a hotfix version for Windows 2000.
When the replace option is used on a Windows NT 4.0 target, the Computer Browser, Net Logon, and
Server services are stopped and started after the name and IP address is changed when failover occurs.
Windows 2000 systems must be rebooted after the failover occurs if the replace option is used.
Since the source name and IP address remain the same when the replace option is used, there are no
name resolution issues to consider as long as the source's IP address is the target's primary IP address after
failover occurs.
Storage Mirroring failover and domain controllers
HP recommends that solutions using Storage Mirroring failover be implemented on member servers
whenever possible. However, there are certain environments where the use of a domain controller as the
source or target is unavoidable. Domain controllers can be successfully failed over with Storage Mirroring
when necessary, but the domain controller functionality is not failed over. Following is a discussion of the
issues that should be considered when implementing a Storage Mirroring failover solution with domain
controllers.
Active Directory
Active Directory domain controllers use a pull-based replication architecture, so there is no risk of Active
Directory updates being sent to the wrong server due to Storage Mirroring failover adding the source's
computer name to the target. The only items to consider are the effects of a given domain controller being
unavailable. A brief outline of some of these issues follows, but a complete understanding can only be
gained by an in-depth knowledge of Active Directory. Active Directory documentation is included in the
Windows Resource Kit.
Active Directory has five FSMO (Flexible Single Master Operation) roles, and each role is assigned to one
domain controller in the domain or forest. Role ownerships can be easily moved between domain
controllers to facilitate changes to the domain controller infrastructure. The five FSMO roles are:
1. Schema master (one per forest)
2. Domain naming master (one per forest)
3. Primary domain controller (PDC) emulator (one per domain)
4. Routing information daemon (RID) master (one per domain)
5. Infrastructure master (one per domain)
D:\>nbtstat -n
TS:
Node IpAddress: [172.16.137.31] Scope Id: []
NetBIOS Local Name Table
Name Type Status
-------------------------------------------
CALLISTO <00> UNIQUE Registered
JUPITER <00> GROUP Registered
CALLISTO <20> UNIQUE Registered
JUPITER <1E> GROUP Registered
INet~Services <1C> GROUP Registered
IS~callisto....<00> UNIQUE Registered
GANYMEDE <00> UNIQUE Registered
GANYMEDE <03> UNIQUE Registered
GANYMEDE <20> UNIQUE Registered