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c7000 - What Chassis?

jasoncm
Occasional Visitor

c7000 - What Chassis?

I am very close to ordering some blades, to the point where I have engaged the failities person here. I've sent him the pdf's around the C7000 asking if he has a preference for single or three phase. He was stumped from the pdfs due to receptacle types and mismatching voltages. Essentially, I have a server room that is stretched to capacity and Im using VMware/Blade as a way to reduce overall power/heat loads as well a method to get to utility computing. (we are building another server room for the future). Plain and simple: I need to know which Chassis to order, and what power infrastructure I need to order to support it (i.e. what recpectacle). I am in Canada, and my facilities person and electrical contractor talk in NEMA, not IEC. I looked at the three phase units and they say 230V, not 208V. Then I look at the pdf and it says both voltages are supported. Confusing - is this the same unit? I also read one document that said there are 2 power supplies on a 3 phase unit, then when I look at the ordering information it has 6 power supplies. Does that mean it now needs 6x L15-30P per chassis? The single phase I've discounted as I cant for the life of me find the products to support the C19/C20 and interface to a standard 110V feed. Right now, I have the facilities person looking at setting up 2x L15-30P receptacles ... so I need to change it quick if it is now 6 receptacles. I have 6 circuits (3 per receptacle) I can use for this. I dont have capacity for more until I decom old servers. Help!
2 REPLIES
ozlace
Occasional Advisor

c7000 - What Chassis?

We have been struggling with sizing power for customers for some time and we got together as a group and put together some thoughts this may or may not :) make it clearer. The problem is that power needs to handle the max the power supplies will use in case of spikes for safety, the fact is the power supplies never pull as much power as what they are rated at. The chassis does indeed come with 6 power supplies, for a single phase configuration it will have 6 plugs at the back IEC-320, for 3 phase it will have 2 L15-30P connectors. The first question we need to as our customer is do they want N+1 or 2N power? The second question is do they want single phase or 3-phase power to the blade enclosure? Traditional servers run with 2N power but we now have an option for the lower amount. Acoording do the current SBW database, 1 Power supply will support up to 2 blades (FH or HH), 2 Power Supplies will support up to 6 FH or 8 HH blades, 3 Power Supplies supports a full enclosure. Add one more and you have N+1 power. If you want 2N power double the above numbers… In either case, we need to have UPS protection for N power supplies. If someone asks why the break points aren't even remind them that there are up to 8 switch modules, 10 fans, and 2 management modules in the enclosure that need power too… My estimate is max base load is about 1000W before we start talking about servers…. The C-Class power supply is rated as requiring 2612W and 12.6A@208VAC on the input side. A single power supply can be fed by an L6-20R power feed. If you want to support 2 or 3 power supplies you need a 40A single phase or 30A three-phase PDU. We cannot use a 30A PDU to feed two power supplies because the rated load is only 24A, and two power supplies will draw 25.2A at full load. If the customer activates Dynamic Power Saver then we could have two power supplies running a max output and we would exceed the National Fire Safety Code limits. Power configuration options: Option 1, the minimum configuration, has no PDUs for the enclosure and one L6-20R power feed for each installed power supply, up to 6. If you need UPS support the R3000 with an add-on battery pack (4U total) will give about 20 minutes run time at full load. A full chassis will need 3 sets (12U total). This UPS uses L6-20R power inputs, so it is a clean solution. A single UPS to support 3 power supplies needs to be rated at 8000W /VA or higher, and they are always hard-wire units, so the installation is much more technical. Option 2 is to use the 40A single phase PDU core that has a Hubble connector on the end (not a NEMA). This is still a standard connector, so APC can easily make a whip to support it. Each enclosure needs two, and the PDU only supports 3 connected power supplies. Option 3 is to go with a 3-phase enclosure with a NEMA L15-30p. With 3-Phase power a 30A feed can supply 24A x 208VAC x sqrt(3) = 8646W, or 2882W per phase which is more than the power supply needs. The sqrt(3) factor is standard, you _really_ don't want a power engineering tutorial….. UPSes of this class will require hard-wire installation. If we have 24A PDUs (L6-30 feeds) then a single PDU can suppor 1 C-class power supply and other connected loads (an EVA 6000 2C8D, for example), so we can minimize the number of power feeds by sharing resources. The HP R5500 UPS uses L6-30 input and output connections so we have a fairly clean configuration here too.
Tony Harvey_1
Occasional Advisor

c7000 - What Chassis?

In the US and Canda you have two options. Either Single Phase high-line 208 or 3-Phase 208V. The Power Cords from the Quickspecs at http://h18004.www1.hp.com/products/quickspecs/12517_na/12517_na.html#Technical%20Specifications Single Phase IEC-320 C19-C20 1.22m (4 ft) 3-Phase 2 x NEMA L15-30p 2.44m(10 ft) The single phase model is typically connected to a PDU such as the HP Modular Distribution Unit 40 Amp 252663-D75 which has a Non-NEMA Locking CS8265C, 50A plug or the HP Modular Distribution Unit 24 Amp 252663-D74 which has an L6-30p connection See www.hp.com/go/rackandpower for more information on these PDUs