We noticed some occasional problem with response of our SQL 2012 STD R2.
Mostly, it works just fine, with stable performance numbers:
arround 100 user connections
logins/sec: between 0 and 2
logouts/sec: between 0 and 2
Therefore I believe SQL works fine, and connection pooling works fine, too.
However, occasionally we observe strange data:
logins/sec rise above 10/sec
logouts/sec still between 0 and 2/sec
user connestions rise up to 1000
CPU rise up to 100%
...therefore we have very slow response time.
I must add, that it happens last 3 days only, with the same load on server.
How could we locate the reason for that behavior?
Could it be DDOS?