Power Requirements for Server Rack

[FragglePete]

Got a bit of a major task on over the next 12 months (which I'll blog about later), but the start of the process is moving the Server Room to a new location.

The room the equipment is going into is about to be gutted and kitted out, but the question that will come my way shortly is how much power will I need?

The old server room has 2 x 42U racks in, and both are just plugged into the wall socket on their own 32A Circuit. Not ideal, but I only have 7 servers at present. This number may grow in the short term, but long term hopefully reduce if we start to virtualize.

The question is, what would be a 'standard' power requirement for each rack? I could work it all out, but servers will be changing over time. One electrical contractor I spoke to a while back suggested have a separate 16A feed for each rack, which seems reasonable.

What power feed do you have each rack in your server rooms?

Looks like I'm going for 4 racks in total; 2 for the servers, 1 for the Core Switch(es) and 1 for the fibre patch panels.

Again, thanks in advance.

Pete

[torledo]

Got a bit of a major task on over the next 12 months (which I'll blog about later), but the start of the process is moving the Server Room to a new location.

The room the equipment is going into is about to be gutted and kitted out, but the question that will come my way shortly is how much power will I need?

The old server room has 2 x 42U racks in, and both are just plugged into the wall socket on their own 32A Circuit. Not ideal, but I only have 7 servers at present. This number may grow in the short term, but long term hopefully reduce if we start to virtualize.

The question is, what would be a 'standard' power requirement for each rack? I could work it all out, but servers will be changing over time. One electrical contractor I spoke to a while back suggested have a separate 16A feed for each rack, which seems reasonable.

What power feed do you have each rack in your server rooms?

Looks like I'm going for 4 racks in total; 2 for the servers, 1 for the Core Switch(es) and 1 for the fibre patch panels.

Again, thanks in advance.

Pete

16A feed per rack should be fine.

infact you could probably power all your equipment off a single 16A feed [depending on rack density], the second feed could be for server power supply redundancy, no ?

how have you been advised as far as UPS to protect the loads ?

[plexer]

my servers are not rackmounted but run off a big ups which is hardwired. Why put your fibre patch panels in a seperate rack.

[Michael]

It really does depend on a lot of factors. For example, some servers I've installed recently are actually much more powerful and less power consuming than the existing servers. In some cases as you have seven servers, I suspect you probably could merge two into one. It depends what they're hosting I suppose.

16A for a 42U rack seems more than enough. Switches generally consume relatively low power (especially modern switches) and many are completely silent as there are no fans at all.

[FragglePete]

my servers are not rackmounted but run off a big ups which is hardwired. Why put your fibre patch panels in a seperate rack.

'cos there is going to be a lot of them.

Completely new backbone going in, 14 fibre runs going into which will all route back to the core. Aiming for a true star topology of the network.

Pete

[powdarrmonkey]

When I worked in a datacentre we supplied racks with a 16A spine each, which was more than enough for a dense (filled with 1U shelves) rack. There was plenty of overhead for spike demands, so you can probably get away with sharing that between two or even three racks in your new room.

It's more important that you make sure the phases are relatively clean, that if you can you have smoothing equipment at source, etc to minimise wear and tear on the kit. And of course, you'll be putting UPSs in too

[localzuk]

We have a 16A supply for our rack - with two 16A plugs, one for each UPS.

[torledo]

When I worked in a datacentre we supplied racks with a 16A spine each, which was more than enough for a dense (filled with 1U shelves) rack. There was plenty of overhead for spike demands, so you can probably get away with sharing that between two or even three racks in your new room.

It's more important that you make sure the phases are relatively clean, that if you can you have smoothing equipment at source, etc to minimise wear and tear on the kit. And of course, you'll be putting UPSs in too

what can be installed specifically to clean power at source ?

[powdarrmonkey]

They're commonly called conditioners and installed either as part of the distribution board or as part of a distribution device in the rack itself.

[torledo]

They're commonly called conditioners and installed either as part of the distribution board or as part of a distribution device in the rack itself.

but a good ups would do power conditioning.

if you need to take the ups offline, then it would be good to have clean power for however long, but you can build that redundancy in with a second power conditioner (ups). Adding a second ups would have the advantage of being cheaper than having a line conditioner installed. Plus the second ups would have battery backup for graceful shutdown.

for a small single server room with 2-4 rack install i'd defintely do with either a N+1 ups if the money is there. If not then 2N ups. 2x 16A feeds coming from 2 ups. i don't know whether you'd need some sort of transfer switch sitting between the ups and the dual psu servers ?

[powdarrmonkey]

but a good ups would do power conditioning.

Yes, it would, but there are things in the room that I'd like conditioned but not necessarily on UPS - switches, monitors for example. A conditioner for those would be cheaper than a UPS and minimise the hassle of maintaining batteries, testing, etc.

[torledo]

Yes, it would, but there are things in the room that I'd like conditioned but not necessarily on UPS - switches, monitors for example. A conditioner for those would be cheaper than a UPS and minimise the hassle of maintaining batteries, testing, etc.

why not have switches and monitors on the ups ? it doesn't add much to the load, and as most ups have some sort of bypass you can still get power to monitors and the like if the ups is in bypass for maintenance or testing. Battery maintenance is a valid point, but there isn't i don't believe a cost saving for going with a dedicated line conditioner.....atleast until you have to replace batteries with the UPS. ;0)

Plus, are you sure about the cost ? dedicated line conditioners are pretty pricey, surge supressers are cheap, but the alternative install cost of a proper TVSS or isolation transformer plus surge supression for the supply to the server room would cost as least as much as a UPS if not more based on the single quote i've had. Told straight off the bat that a line conditoner would be much more costly than an isolation transformer.

sorry for the inquistion, but i'm looking into getting cheap [as possible] clean power for the supply feeding our server room. And curious as to recommend products that would fit the bill. without breaking the bank.

[powdarrmonkey]

why not have switches and monitors on the ups ? it doesn't add much to the load, and as most ups have some sort of bypass you can still get power to monitors and the like if the ups is in bypass for maintenance or testing. Battery maintenance is a valid point, but there isn't i don't believe a cost saving for going with a dedicated line conditioner.....atleast until you have to replace batteries with the UPS. ;0)

Maximum runtime. I don't care if the core switch and monitors go off, or periphery servers that don't matter, but I do care if the file server goes while flushing the disk for example. Don't under-estimate the power requirements for a switch

Plus, are you sure about the cost ? dedicated line conditioners are pretty pricey, surge supressers are cheap, but the alternative install cost of a proper TVSS or isolation transformer plus surge supression for the supply to the server room would cost as least as much as a UPS if not more based on the single quote i've had. Told straight off the bat that a line conditoner would be much more costly than an isolation transformer.

A rack mount conditioner will set you back something around £50-£150 per rack, versus £300-£2k for a UPS. At that rate, I'd even condition my UPS feeds, since if there's an almighty surge that kills things I'd much rather it be a fifty quid conditioner.

You're right that a full supply protection in the wall would be more expensive though. But a conditioner per rack plus one on the desk for other bits and pieces really isn't so much of a problem, is it?

sorry for the inquistion, but i'm looking into getting cheap [as possible] clean power for the supply feeding our server room. And curious as to recommend products that would fit the bill. without breaking the bank.

Samson PS10 19" Rackmount Power Conditioner - DV247.COM ?

[TNE]

Hello Pete,

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Thanks