HGST Deskstar NAS Drives?

[farmerpling2]

Seagate Enterprise (He and 2.5") also uses 5V more than I thought they would, though their 5V usage bounces around some....

 

[LIGISTX]

Well I am planning either 6 or 7 on a RM550. Should suffice, yea..?


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[Chris Moore]

Well I am planning either 6 or 7 on a RM550. Should suffice, yea..?


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A few years ago I built a system with the intent of being as power conservative as possible and did fine calculations about the start current of the drives because that was the big power draw in my system as it had 12 drives.
I needed to get a single rail 650 watt power supply to be sure to have enough available current at start. Under load, in normal use, the system was only using between 100 and 150 watts. Only at startup was it ever even a possible concern. If you buy a good power supply that is Gold or Platinum rated, you should be fine with 550 watts. The rated wattage of the supply isn't going to make it draw more electricity.

 

[LIGISTX]

A few years ago I built a system with the intent of being as power conservative as possible and did fine calculations about the start current of the drives because that was the big power draw in my system as it had 12 drives.
I needed to get a single rail 650 watt power supply to be sure to have enough available current at start. Under load, in normal use, the system was only using between 100 and 150 watts. Only at startup was it ever even a possible concern. If you buy a good power supply that is Gold or Platinum rated, you should be fine with 550 watts. The rated wattage of the supply isn't going to make it draw more electricity.

Yea it's inky going to draw enough to power the components. And yea a 550 watt has to be enough. If you can power a full on gaming PC with 550, I can't see a few hhd's start amps killing it lol.


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[Chris Moore]

Yea it's inky going to draw enough to power the components. And yea a 550 watt has to be enough. If you can power a full on gaming PC with 550, I can't see a few hhd's start amps killing it lol.

You might be surprised how low the ratings on some of the smaller power supplies can be, especially the ones that don't have a single rail. You also don't ever want to exceed 90% of the rating for safety reasons.

 

[LIGISTX]

You might be surprised how low the ratings on some of the smaller power supplies can be, especially the ones that don't have a single rail. You also don't ever want to exceed 90% of the rating for safety reasons.

Yea. Rm550 is single rail.


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[Chris Moore]

It has been several years since I looked at it because the server chassis I am using now has a power supply that is rated for like 1000 watts and it is supposed to be able to power a full load 1500 RPM drives that use a lot more power. Anyhow, if I recall correctly, the power concern that I had when I was looking at ATX power supplies back then was more about how much power was being pulled on the 5 volt rail than on the 12 volt rail because they usually don't have as much power available on the 5 volt rail and that was more the limiting factor than anything.

 

[LIGISTX]

It has been several years since I looked at it because the server chassis I am using now has a power supply that is rated for like 1000 watts and it is supposed to be able to power a full load 1500 RPM drives that use a lot more power. Anyhow, if I recall correctly, the power concern that I had when I was looking at ATX power supplies back then was more about how much power was being pulled on the 5 volt rail than on the 12 volt rail because they usually don't have as much power available on the 5 volt rail and that was more the limiting factor than anything.

True. I think the rm550 does 25 amps on the +5


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[farmerpling2]

Most drives used 22w to startup or less.

A few drives like HGST use 30W. I use HGST with many drives without a problem. Even better you can use low power startup on many drives now days and they take longer to come up but use a lot less power.

The average startup power consumption on 118 disk drives on the Disk Drive/Performance Spreadsheet is 20.42w, mean is 21.6w. The WD Red NAS 5400 RPM 2.5" 1TB uses 5 watts startup, 1.4 active, and 0.6 idle.

A good gold PS will do you well. I would not buy a platinum, unless it had a 15 year warranty!

 

[farmerpling2]

The rated wattage of the supply isn't going to make it draw more electricity.

FWIW, it does affect the efficiency of the PS. Linear PS work the most efficiently at 50% load. So a 1Kw PS is most efficient at 500w.

That being said, the efficiency, on either side of the knee is just a few percent. In other words penny's, not dollars of inefficiency.

 

[Chris Moore]

FWIW, it does affect the efficiency of the PS. Linear PS work the most efficiently at 50% load. So a 1Kw PS is most efficient at 500w.

That being said, the efficiency, on either side of the knee is just a few percent. In other words penny's, not dollars of inefficiency.

I understand, but that isn't what I was talking about. I was saying that a 1000 watt power supply doesn't mean it draws 1000 watts. The power draw is based on the components connected to the supply, not the rating of the supply, except with regard to efficiency which I was not going into because it is more complicated than I wanted to get into.

 

[LIGISTX]

Most drives used 22w to startup or less.

A few drives like HGST use 30W. I use HGST with many drives without a problem. Even better you can use low power startup on many drives now days and they take longer to come up but use a lot less power.

How do you use low power startup?

Also on bummed, I didn't jump on the deal fast enough, the HP server is now 199 instead of 169! Still a great deal but at 169 it's such a joke of a deal lol.


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[farmerpling2]

OK - No problem.

 

[farmerpling2]

How do you use low power startup?

Different vendors have different ways. You have to read the specs and they talk about how to set it up. For some, you can use the camcontrol program to program them. Some have jumpers, though, I think that is going away.

 

[danb35]

Linear PS work the most efficiently at 50% load.

...but linear power supplies haven't been used in computers for decades, so this is irrelevant.

Edit: Supermicro achieves 96.x% max effiency on their Titanium power supplies, and yes, that is at around 50% rated load. But even at 10% load, it's still 92% efficient. The difference in efficiency at different load levels simply isn't a significant factor.

 

[farmerpling2]

...but linear power supplies haven't been used in computers for decades, so this is irrelevant.

You are SOOO correct. I meant switching but I typed linear. Guess it was one of those days.

Edit: Supermicro achieves 96.x% max effiency on their Titanium power supplies, and yes, that is at around 50% rated load. But even at 10% load, it's still 92% efficient. The difference in efficiency at different load levels simply isn't a significant factor.

Which is why I said the below in a prior message.

That being said, the efficiency, on either side of the knee is just a few percent. In other words penny's, not dollars of inefficiency.

Hope that clears it up.