You need 2 or 3 to make it easy on 10 man.
If you have a melee DPS like a DK or Pally, they can tank P1.
DK go blood presense or Pally turn on Righteous Fury and tank. Bosses swings are very 5 sec so its super easy to heal a DPS tank. Have 1 tank taunt double attack in P1.
Going into P2, the tank that's tanking must NOT have any break stack and have the other tank taunt for double strike. You need 2 real tanks for P2.
---------- Post added 2011-02-27 at 06:43 AM ----------
On another note, tanks that tanking in P2 must be topped off or using cooldowns.
Our cooldowns go like this
Lay on Hands for 1st feud
Ardent Defender for 2nd feud
Guardian Spirit for 3rd feud
Lay on Hands from our Holy Pally for 4th feud and thats all we need and we push it to P3 and Aradent Defender is back up for living little longer during P3
In our 25-mans, we have two normal tanks and myself (Unholy DK) tanking. With the > 10k life mechanic, Chimaeron's melee attacks can't kill you, whether or not you're a tank. Death Knights are a smart choice to be the DPS-Tank as they can perform their typical DPS "rotation" in their tanking presence (for extra threat) and you'll need all the DPS you can get for the final phase.
My job is to soak break stacks during anything that isn't feud so that the tanks have a higher chance of surviving during it.
We go:
DPS-Tank pulls
Tank 1 taunts on double attack
DPS-Tank taunts back after double attack
(repeat)
<feud>
Tank 1 tanks during the feud
Repeat this process, but use your second tank instead of Tank 1 every other phase. That way the 1-minute break debuff will fall off in plenty of time.
Yeah this would never be solo tankable because of Break and the fact that he still melees during Feud.
Blonk's strat is how we do it, even on 10-man. We found trying to treat the encounter like normal (2 tanks) meant our tanks got insta-gibbed every Feud, cooldowns or not.
The other way to do it is to use 3 real tanks in 10m, one double attack tank as normal, one guy to start, one guy taunts on shutdown then continues to tank in the normal phase until the others break falls off, who then taunts. Rinse and repeat. You lose the advantage of a 'dps' but it resolves any threat issues in p1 and survivability issues you may have in p2. Really depends on your setup. We're doing it with a warrior dps at the moment, and its really horrible for the dps (I'm having to cower on CD on take every salv there is)