Colo Power Layout?
Might as well ask here, too.
Taken from a conversation on IRC (not #e) today. Most of this is me, with 2 other voices jumping in.
Does anyone see a downside to this idea?
JB
= = =
So, I've got this question about data center rack layout... We've got racks with 2 circuits in them (10 outlets on one, 9 on the other (after you take out outlet for the rack fan). We've got stacks of machines with dual (redundant) power supplies. Most of the machines are powered with a Y-cable going to both power supplies.
Can you see where this is going? ...
Is there any reason any of you can think of to NOT connect each Y power cable to 2 different machines, and then to make sure that each machine is powered off of 2 different circuits? That way - by my figuring - you'd have to both lose a power supply AND lose the opposite circuit for a machine to go down.
(I also have this thought that there might be some advantage to hooking the 1st power to machines A and B, the 2nd to B and C, the 3rd to C and D and so on, to the limit of the Y to reach back to A... But I'm not near so certain about that.)
someone else> usually have machines with pairs of PSUs connected to disparate power sources
Right. The Y cables (long Dell's standard choice which you had to deselect while ordering) give you HW redundancy but leave you at the mercy of your power source.
As well, as we have 2 racks, 38 outlets and 22 dual-power-supplied machines, we kinda HAVE to go with Y power.
(and something like 1/3 to 1/2 of the racks are still empty...)
So if I go with my concept, we can hook up 22 machines to 22 outlets and STILL have each of them powered off of multiple PDUs.
I don't see the lose, but I've never thought of this before.
2nd Someone> if you have remote power controllers, there is a new issue ;)
Remote power is one of the reasons to do the ab/bc/cd/da thing. I could turn off any 2 to get a machine cycled.
Taken from a conversation on IRC (not #e) today. Most of this is me, with 2 other voices jumping in.
Does anyone see a downside to this idea?
JB
= = =
So, I've got this question about data center rack layout... We've got racks with 2 circuits in them (10 outlets on one, 9 on the other (after you take out outlet for the rack fan). We've got stacks of machines with dual (redundant) power supplies. Most of the machines are powered with a Y-cable going to both power supplies.
Can you see where this is going? ...
Is there any reason any of you can think of to NOT connect each Y power cable to 2 different machines, and then to make sure that each machine is powered off of 2 different circuits? That way - by my figuring - you'd have to both lose a power supply AND lose the opposite circuit for a machine to go down.
(I also have this thought that there might be some advantage to hooking the 1st power to machines A and B, the 2nd to B and C, the 3rd to C and D and so on, to the limit of the Y to reach back to A... But I'm not near so certain about that.)
someone else> usually have machines with pairs of PSUs connected to disparate power sources
Right. The Y cables (long Dell's standard choice which you had to deselect while ordering) give you HW redundancy but leave you at the mercy of your power source.
As well, as we have 2 racks, 38 outlets and 22 dual-power-supplied machines, we kinda HAVE to go with Y power.
(and something like 1/3 to 1/2 of the racks are still empty...)
So if I go with my concept, we can hook up 22 machines to 22 outlets and STILL have each of them powered off of multiple PDUs.
I don't see the lose, but I've never thought of this before.
2nd Someone> if you have remote power controllers, there is a new issue ;)
Remote power is one of the reasons to do the ab/bc/cd/da thing. I could turn off any 2 to get a machine cycled.