This metric tracks the amount of data waiting to be sent from the principal database to the mirror. This is known as the send queue. Read more
Author: Grant Fritchey
Current status of mirroring
Mirroring systems can go offline. This metric returns the current state of the mirroring system so you’ll know from a single value what the current status of your mirroring environment is. Read more
Current role of a database
This metric allows you to keep track of the role of a given database within your mirroring set up. The single value returned tells you whether the database is the principal or the mirror. Read more
Status of the witness
This metric returns a single value that tells you whether the witness is connected, disconnected or unknown. Knowing if it is offline can be as important as knowing if your mirrored databases are available. Read more
Low physical/external memory
Determining if your operating system is causing memory issues within your SQL Server instance can be a challenge. One way around it is to use the sys.dm_os_ring_buffers to show when server memory is low. Read more
Low virtual memory
Determining if your SQL Server instance is experiencing memory issues within the SQL Server Virtual Address Space (VAS) can be a challenge. One way around it is to use the sys.dm_os_ring_buffers. Read more
How to write a custom metric
So you’ve seen the example metrics provided on this site, but what if you want to create your own from scratch? Red Gate provides documentation on its… Read more
Processes in a runnable state (worker query)
This metric measures the load of running processes within SQL Server. It doesn’t show any specific problems, but can act as a measure of the pressure being put on your SQL Server instance. Read more
Processes in a runnable state (scheduler query)
To determine the general load on the operating system you can get a count of the processes that are in a runnable state. Read more
Out of memory errors
The number of out of memory errors that have occurred within a rolling five minute window. If you just want to keep an eye out for any memory errors, you can watch the ring buffers for the Out of Memory error alert when it gets registered there. Read more