How many blade enclosures can you fit in a rack

The answer is - it depends. IBM previously allowed a mix of their older blades with the newer HS22 blades but they've since changed it to state that with the BladeCenter E (8677) chassis, the HS22's are allowed when all of these conditions are met:

1) when placed in their own Power Domain (meaning - only HS22's in blade bays 1-7 or 8-14) 2) when 2000W power supplies or higher are used 3) when the Advanced Management Module (AMM) is installed.

A caveat to the above is if you upgrade your existing chassis to the 2320W power supplies, then you will be able to put in HS22's anywhere you want in the chassis - however the 2320W power supplies require more power than the 2000W power did, so you'll need to make sure you check your power load in your rack.

Hope this helps. Come check out my blade specific blog at http://BladesMadeSimple.com

Water + Electricity = Disaster

Water cooling allows for greater power density than air cooling; so figure out the cost savings of the extra density (likely none unless you're very space constrained). Then calculate the cost of the risk of a water disaster (say 1% * the cost of your facility). Then do a simple risk-reward comparison and see if it makes sense for your environment.