The above poster is incorrect. you will not just be going gate to gate. as this is your first stop in canada, vancouver is where you will clear customs and eventually 'land'.
the process though is fairly simple. you will go through customs and be directed to immigration, where you will sign the landing papers, answer a few questions and give your canadian address. after you are finished you will collect your baggage, get it approved at customs, then drop it off not too far away where it will be directed onto your next flight. then you can go to your gate.
2.5 hours is enough time to do all this, and get yourself a coffee as well. if your manila flight is delayed, there is the possibility that your luggage will not make the 2nd flight, but it's okay because they will send it on the next flight, and if necessary deliver it to your home.
congratulations and welcome to Canada!