Sql Server Consolidation and Configuration Part 2 Network
An often neglected part of Consolidation is the network
configuration of a server. If you have mirroring set up this is particuarly
important because the network throughput can be in the same magnitude of the
transaction log throughput.
Generally if I am limited to four NIC's available I will team
two and make them available for general application access, allocate one to an
external backup device (iSCSI or a CIFS UNC path) and one for a dedicated
connection to the mirrored server. This kind of configuration is for a very
basic setup. If there are replication topolgies in place or a scaled out BI
Infastructure on a bigger server I would also look at dedicated NIC's for this
kind of trafiic. I always set my network cards to Full Duplex.
To get round the issue of legacy applications that dont
support the failover partner syntax with mirroring, I often use DNS aliases that
I talk about in my previous blog
post. When I'm utilising mirroring over a WAN and I want to reduce the network
sent over the very precious WAN link, I will disable encryption and utilise
riverbed hardware as mentioned here.
To force the routing of traffic via a dedicated DR connection I make an entry in
windows hosts file for the mirrored server.
While this is not meant to be an exhaustive list, but it does
illustrate a few best practices i've discovered. If anyone has any more tricks
they would like to share, please let me know.