Specifics:
2 SQL Server Nodes, 2014 (12.0.2480.0)
1 Share witness (on separate subnet)
1 Cluster
1 Listener
I have been testing the response time to failovers – both manual (right-click, fail over in SSMS) and Automatic (shut down the primary host). The way I am testing response is to have a SSMS query running on my desktop, connected to the listener querying a small table and hit execute.
The Query response time, from execute to receiving the result, has been between 8 and 14 seconds based on my testing. My previous experience (in a separate environment) showed around 2 second fail over times in a very similar configuration.
Availability DB is 200Mb and is not actively used. The nodes are synchronised.
SQL Server Hosts: Windows 2012, 2 cpu, 8gb RAM.
Questions:
1: It’s a big question but what should I expect for a ‘normal’ fail over time. Keep in mind this scenario is about as simple as it gets.
2: I can get reasonable ‘outage’ times using SQL Server logs and Event viewer, but does anyone know of a single source that says ‘Fail over started at time X and completed at time Y’? I need to know specifically how long the listener was un-available and requests were going un-handled.
3: As it stands an 8 to 14 second ‘outage’ could cause some applications to time out. Or am I being un-reasonable? I am seeing the very simple query in SSMS to time out with this:
/*
Msg 983, Level 14, State 1, Line 2
Unable to access availability database 'DATABASE' because the database replica is not in the PRIMARY or SECONDARY role. Connections to an availability database is permitted only when the database replica is in the PRIMARY or SECONDARY role. Try the operation again later.
*/
Undoubtedly you are going to need more information, please let me know what else you might need.
Thanks in advance!