When you setup a monitoring system for SQL Server, you often use thresholds to determine when an instance is healthy. You might say that you want to be alerted when CPU use is over 90% or when there’s only 10% of disk space left. The trouble with these thresholds is that they will often throw off false positives, or send you an alert when really nothing is wrong. Simple thresholds often have to be tuned to the individual instance, since a server with 10 TB still has 1 TB of space left at 90% disk use.
Baron Schwartz blogged about this issue in[Read more...]