Count data that match with event

One super easy way to do this is with a stats profile.

1. Create a stats profile -> Local Traffic -> Profiles -> Other -> Statistics. Give it a name and define at least one field. (ex. "stats-test", field 1 = "triggered")

2. Assign the stats profile to the VIP.

3. In an iRule, in the event you want to capture, increment the stats profile field(s).

   STATS::incr stats-test triggered
   

After some time, look at the accumulated value in TMSH:

tmsh show ltm profile statistics test-stats

Example output:

-----------------------------------
Ltm::Profile Statistics: test-stats
-----------------------------------
triggered  14

.

You could also do this with iStats, a later and more powerful version of the above: https://devcentral.f5.com/wiki/iRules.ISTATS.ashx .

Or you could increment a table value, which you'd then be able to read from an iRule.