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Proper configuration for database mirroring with witness and crossover cable for mirroring traffic

I am trying to setup a server with database mirroring in SQL 2005, but I need to have the mirroring traffic go over a crossover cable between the principal and the mirror.  DNS has an entry for the principal and mirror for these mirror interfaces so that they can see each other.

Principal - 3 NICs - Public, Private, Mirror
Public x.x.x.x, Private 10.10.1.101 (DB1.DOMAIN.LOCAL), Mirror 192.168.0.101 (DB1-DBM.DOMAIN.LOCAL)

Mirror - 3 NICs - Public, Private, Mirror
Public x.x.x.x, Private 10.10.1.102 (DB2.DOMAIN.LOCAL), Mirror 192.168.0.102 (DB2-DBM.DOMAIN.LOCAL)

Witness - 2 NICs - Public, Private
Public x.x.x.x, Private 10.10.1.103 (DBWITNESS.DOMAIN.LOCAL)



Do I need to add a third NIC to the witness to allow the witness to do its job?

If I do _not_ need a third NIC, what settings would I use when I "Configure Security" in the Mirroring setup to ensure that the witness will do it's job?  It seems like if I use the DB1-DBM and DB2-DBM in the settings, the witness will never be able to communicate with them since it does not have access to the 192.168.0.x network.
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lordicarus
Asked:
lordicarus
1 Solution
 
lordicarusAuthor Commented:
Actually I figured this one out.  In reality you _could_ set this up by creating a reference in the hosts file on the witness server to point db1-dbm and db2-dbm to the 10.x addresses, and it would be able to tell if the servers were up and sql was responding, but since it's not on the same 192 network it doesn't ensure that db1 and db2 are actually able to communicate over said crossover.  

The solution would be to put the three servers on their own VLAN and add a third NIC to the witness server.  Third nic would be required since repurposing the public or private nic as the dbm connection would not be allowed (due to client needs) and since the issue with doing something like the hosts file thing would still be an issue if it wasnt connected to the same vlan.
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