Mirror Semaphore Granted and Waited

Number of times that a request for a mirror semaphore was granted immediately and the number of times the semaphore was busy and the task had to wait for the semaphore to be released. The “% of total” column is the percentage of times the device the semaphore was granted (or the task had to wait) as a percentage of the total number of mirror semaphores requested. This data is meaningful only in SMP environments.

Adaptive Server uses the semaphore only when either disk mirroring is enabled or when disk I/Os are delayed. Disk mirroring is enabled when you change the configuration parameter from is “disabled” default.

A large percentage of I/O requests that waited could indicate a semaphore contention issue. You may want to try redistributing the data on the physical devices.