Hello, we have a site, it works well most of the time but from time to time when it usually gives a one minute drop, we are using IIS 8.5 as a server and we work all ASP.NET technology.
Our servers are hosted at Rackspace and before arriving at the server we have a% activated% co that sends the requests to two servers They have this same site in both running.
I have armed on both servers, a Load Balancer Round Robin with several Performance Monitor , between this Counters and Request Current to monitor what happens, when Request Queued warns that one of the two instances falls then entry to see the pingdom , we realize that always falls an instance because we have another alternative site that also falls and the tail of Performance Monitor reaches the limit.
The value of aspv4.0 and Request Queued sometimes in a few seconds reaches 3000 and that's when the site falls, is it possible that it is an attack DDOS ?
EDIT: I add images of the metrics:
You can see in Request Current Y Request Current an equal number but quite high indicating that they are not processed for some reason, on the other hand you can see the metric Request Queued that has the number 39, indicating that you are restarting the apps many times.
These are other metrics that I found and that I am analyzing:
I hope you can give me a hand and in any case that they need additional information, I am available.