I just wanted to get some sort of idea on how power should be distributed on Equallogic PS6510.
There are three PSU at the back of the unit.
PSU1 plugs in to PDU A
PSU2 plugs in to PDU B
PSU3 plugs in to PDU A or B
Problem is that 6510 requires power from at least two of these PSU's at all times to work.
If we have two of these plugged in to the same PDU and we were to lose power to this PDU, it will take PS6510 down!
Where is the redundancy in this? Is there any kind of solution to this?
Yes, that is also a good option, provided that the UPS is adequately sized to meet the power requirements of a full load from the array.
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Yes, a single UPS that has two power inputs (PDU_A & PDU_B) would work in the same manner, provided that the single UPS is rated to meet the requirements of the full load of the Array (and any other HW you are attaching to the UPS).
The suggestions that were used in this thread were only in regards to the original post question to use a 2 UPS model. Since there are UPS’s on the market that have multi PDU capability, than a single UPS with this option is just as good as having multiple UPS’s (I would guess that it would be easier to manage/maintain in the long run too).
You would need either a third UPS or incorporate an ATS (Automatic Transfer Switch).
If using a third UPS you would be faced with the problem of “where do I plug the third UPS into” since most data centers usually only have two separate circuits. If this is the case, you could use an Automatic Transfer Switch (ATS).
The ATS basically has two power cords and some outlets, and you plug it into two power sources; if one source fails the ATS switches to the other one so the outlets remain powered.
This is not an endorsement but this link shows APC’s offerings for an ATS: www.apc.com/.../index.cfm
If you are limited to only two UPS’s, other customers have used the ATS with success (although it’s not officially tested or endorsed by Dell). You can configure the two UPS and an ATC as follows:
Connect the ATC two power cords to UPS1 and UPS1, than connect the Array PS0 to UPS1, PS1 to the ATC, and PS2 to UPS2 (the ATC spans both UPSs, and only one PS is connected to it). Note that this would require that a single UPS can carry the full load of the array (two PS’s)
If you are going to purchase a third UPS, but still only have two circuits, then the configuration would be different, where the ATC would span C1 and C1, and UPS 1 is in C1, UPS2 is attached to the ATS, and UPS3 is in C2, which each PS plugged into a separate UPS. This would be preferred over the two UPS option.
Ideally, you would have three circuits and three UPS's
For sizing of the ATC, each PS of the PS6510:
Input voltage: 100 to 240 VAC (auto-sensing)
440 watts DC output
Maximum input power: 0.7 KVA
Input current: 7 – 3.5A
Joe, this is very helpful. Thanks.
Second diagram shows you are using 3 UPS devices.
Can we not use 1 UPS device which plugs in to the ATS and all 3 power connections from Equallogic can plug in to UPS as shown in the image below?
Hi again Joe,
My manager has asked me an interesting question about this:
Do we even need the ATC?
Can we not use a suitable UPS where we can use two inputs coming from both PDU A and PDU B. The plug in all the cables from PS0, PS1 & PS2 in to the UPS?