How many blades can a c7000 with four power supplies support?

[Michael1]

Hi,

We wish to add more blades to one of our c7000 chassis. At present all of the chassis are fitted with FOUR power units per site which cater for up to nine BL460c blades. Would anyone know the maximum number of blades this arrangement is designed to handle?

-M

[Ali]

Hi Michael,

4 power supplies are sufficient to power up the fully populated c7000 enclosure in N+1 or No redundancy configuration. so depending on your power redundancy/AC redundancy and other power configuration no of power supply required will varry.


However, it's always a good idea to calculate the amount of power and power supplies required in your enviornent by running the power advisor
www.hp.com/go/hppoweradvisor

thanks,
Aftab

[Ali]

for more info, check c7000 power guide
http://h20000.www2.hp.com/bc/docs/support/SupportManual/c01543629/c01543629.pdf

please don't forget to assign points if you think information provided is helpful..:)

cheers!
Aftab

[Emil Velez]

THe whole enclosure full of blades but you are flying without a parachute. No redundancy if a power supply fails. They are reliable but people win the lottery too.

I assume this is not a mission critical system that is to be kept highly available.

Can I assume that you will also be using all of the fans ? Same issue with fans.

[Trygve Henriksen]

How much power do you use today?

And will the new servers be of a similar specification?
(Our, with two Cisco Gigabit switches, two fibre switches, full complement of fans and PSUs and 7 servers averages 1000W usage, and lists nearly 3KW as 'allocated')

If you have 4PSUs, you should be able to draw nearly 4800W and still have full redundancy.

If you're worried about startup powersurges, you can set delays on the 'power on' startup so that they start at intervals.
(It's a good idea to set a delay, anyway, if you have external components, such as SAN libraries that are slow to initialise)

[akash1980]

May be it helps.

http://virtualcloudzz.blogspot.com.au/2012/12/hp-power-calculater-advisor-tool_10.html

[Casper42]

The reason you did not get a simple answer to this question is because every blade is different.

A BL460c G7 with 1 CPU and 1 DIMM and 1 HDD will obviously need less power than a similar model with faster CPUs, 12 DIMMs, 2 CPUs, 2 HDDs and a FC HBA Mezz Card.

When a blade is inserted into the enclosure, the iLO inventories the HW and detrmines how much power all your componentd would need at MAX usage.  This is all added up and you get a "Power Allocation" for the blade.

This Power Allocation is checked against the enclosure's Available Power and if there is enough power, the blade is allowed to be powered on and the Available Power is reduced by the amount of the blade's Allocation.  Simply repeat this process until you run out of Available Power.

Available Power in AC Redundancy mode is N/2 where N is 1 power Supply (so 4 x 2400W = 9600W/2 = 4800W Available)

Available Power in Power Supply Redundant is N-1 (4 x 2400W = 9600W-2400W = 7200W Available)

Available Power in No Redundancy is simply N (9600W using 4 x 2400W)

Keep in minds Fans, OAs and Interconnects all get power as well.

So the easiest way to answer your question is to look at your Available Power, and then look at a blade that is similar to what you want to add, and see if that blade will put you over the max or will still be under the max.

Keep in mind these Allocations are all based on MAX usage.  You will never actually draw all blade's max at the same time.  Actual usage will often be only around 50% of the Allocation/MAX.