You should keep the witness server in the same site as the principal database. The main reason for this is having the witness on the same site as the secondary in the event of failure would halt transactions on your principal.
From the mirroring best practices:
Loss of the mirror and the witness
Assume you have configured database mirroring with a witness. When the mirror is unavailable, the principal runs exposed. While the mirror is unavailable, if the witness is also lost, the principal becomes isolated and can’t service the clients. Even though the principal database is running, it is not available to the clients. If you attempt to connect to the database, you get the message “Database <dbname> is enabled for database mirroring, but neither the partner nor witness server instances are available: the database cannot be opened.”
Friday 23 October 2015
Wednesday 21 October 2015
SQL Server 2016 Getting tempdb a little more right
If I look back on my career, and think about the most common SQL Server bottlenecks – be it customer environments, community members I've helped online or in person, or my own in-house systems – tempdb would have to rank in the top 3, and possibly an outright winner.
Part of this problem is the ridiculous defaults in all major versions of SQL Server to date. Here are the properties of the tempdb files for a 2014 SP1 system I created recently:
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