I disagree. A simple way to get accurate, quantifiable data is to shadow a user
and use a stopwatch. Don??™t have a stopwatch? Many cell phones provide some sort of
stopwatch functionality, as do many modern watches. Ideally, the application would have
some sort of stopwatch functionality that you could enable with a certain startup flag.
If you believe user perception is worthy of consideration when selecting a databasemirroring
mode (and I think user perception should be considered), you should consider
the following situations:
CHAPTER 8 n DATABASE MIRRORING 224
??? Low user downtime: If the user experience is one of the major business drivers that
you must consider, then running database mirroring in High Availability or High
Protection mode (both use synchronous communication) will definitely have an
impact on that user experience. Depending on the network factors and the location
of the mirror database, the impact on users could be significant. Even what
seems like a minor network delay of 50-100 milliseconds (yes, milliseconds) could
result in a visible delay for users.
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