Forum Discussion
CirrusMonitor response time
Hi All
Currently I have configured a monitor that calls a configured .jsp file and expects a certain response.
What I have seen is that under certain conditions the monitor is responding as successful even though it is taking a bit longer to respond due to issues on the Application Layer.
My question is thus, what monitor configuration should I use that if the .jsp file is taking to long to respond it will see it as down and take required action.
Thanx
- P_K
Altostratus
Can you provide more info on your monitor strings?
SLCurrently it is simple https monitor that does a query to a .jsp file and expects a string back of "ALL OK".
What the customer says they have experienced is that they had scenarios where the the query would still pass but take a long time to respond and that is due to the application having issues but still online.
So I am looking for something I can add to the monitor that will see that the query is taking 5seconds longer than what it should and see that as a failure.
I know there is WMI, unfortunately these are not Windows Servers.
jaikumar_f5Noctilucent
You should know the timeout value. Timeout usually is configured as 3x+1, where x is the interval value.
If your interval is 15 and timeout is 46, it means, the F5 monitor sends Get request every 15secs, and the recv string if got, it marks it as UP.
If not got, it again polls for 2 more attempts (i.e)till the timeout value is reached. So if by 3rd attempt the recv string is not recieved, the member will be marked as down.
You can have this verified by enabling the monitor logging on the node. The logs will be captured on /var/log/monitors/.
- P_K
Did you try with just "200 OK" as receive string? If not give it a try and see if that works. Also as said by jaikumar_f5 you can tweak your timeouts higher than 5 seconds and see if that works.
- SL
The timeout is using the default 5 seconds. The customer wants me to make the timeout lower, my concern is that I am going to flood there logs with any timeout shorter and was wondering if there was a different setting that can be used.
- jaikumar_f5
Like I said, if monitor is failing even on the final attempt, only then it will mark it down. And once it gets a positive response on the 1st attempt, it marks it up.
Here's the F5 explanation:
BIG-IP LTM monitors
- At regular intervals, the bigd process sends a request to each monitored object and evaluates the response.
- By default, BIG-IP LTM monitors use a 3:1 timeout:interval ratio.
- If the bigd process receives at least one correct monitor response during the timeout interval, the object is considered Available.
- If the bigd process does not receive at least one correct monitor response during the timeout interval, the object is considered Unavailable.
Regarding your issue, its a jsp file, similar to other asp or php pages but containing javacode. If your requirement is to mark it down when its really down for 5 seconds, then your timeout should be 5 seconds. You can keep your interval to 5sec also instead of 1sec. But F5 recommends 3x+1 timeout value. Hope this should work.
- SL
Thanx Jaikumar
I will relay message to customer and work on how we can customize the monitor as per there requirements.
