NA Server sudden stoppage

[Let'sgoflying!]

Is it physically harmful to a server to have a sudden power loss? (Its an HP ML350-T09, there is also a managed switch, a firewall, a modem)

I am wondering if I really need a UPS with 'graceful shutdown'. Running the budget pretty close.

(I can live with any data loss if it means a document I am working on, or an invoice being entered is lost.) Just wondering if there are long-term consequences to the devices.

 

[weilke]

I am wondering if I really need a UPS with 'graceful shutdown'. Running the budget pretty close.

Even fairly basic UPS units offer automated shutdown. It just needs to be set up.

 

[RJM62]

Is it physically harmful to a server to have a sudden power loss? (Its an HP ML350-T09, there is also a managed switch, a firewall, a modem)

It can be.

I am wondering if I really need a UPS with 'graceful shutdown'. Running the budget pretty close.

Yes, you do. But almost all UPSs provide shutdown signals to the computer. The "graceful shutdown" is performed by the computer upon receiving the signal. So all you need is a UPS of sufficient capacity that provides the shutdown signal. You then have to physically connect it and configure the shutdown in the computer's power settings.

(I can live with any data loss if it means a document I am working on, or an invoice being entered is lost.) Just wondering if there are long-term consequences to the devices.

The main risk would be loss or corruption of open documents, followed closely by filesystem damage. But many electrical and electronic devices can be damaged by undervoltage as well as by overvoltage. So if you use a UPS (which you should) you should also connect the data link and configure the automatic shutdown.

I usually set the shutdown to start five minutes after line power loss. That gives a human enough time to save any documents if the machine is being used, but still retains plenty of power to execute the shutdown (assuming an adequate-size UPS) if the machine is unattended.

By the way, regarding modems, firewalls, switches, VOIP adapters, and other relatively low-draw devices, APC (and probably other manufacturers) make special UPSs for these devices that are optimized for longest uptime under low draw. I think they're a good investment. I use an APC BGE 90M for those type of devices.

Rich

 

[denverpilot]

The sudden "off" isn't usually nearly as damaging (other than instant heat load that isn't being shed) as the brown outs, bumps, and generally crappy AC line voltage that usually transpires "around" such an event. Obviously if you have important data on the system and aren't using solid file systems that can handle recovery on their own with minimal data loss upon return to service, that's a different problem.

 

[Let'sgoflying!]

Jeez it is all so confusing. Some (Powerchute) don't work on certain devices, some devices need pure sine wave inputs, they want to know the wattage but looking at the spec sheet multiple wattages are listed. I'm also limited to $500 actually that is over what I can spend; waa-waaa! Going for a second glass of w(h)ine.
Thanks for info.

 

[denverpilot]

If you're limited to $500, I'd just pocket it and use it to repair the server. Can't find a decent sine wave UPS for under $1100 that's built beefy enough to keep most servers running for any significant length of time.

We're discussing putting an individual 2200 Ah UPS on *each* server for 30 minutes of run time before generator power is needed for the hyper-critical call center stuff, and we're cheap as all get out when it comes to hardware.

When you say "server" do you mean a real server (hardware raid, rack mount, dual power supplies, etc...) or just a desktop class machine sitting under a desk "serving" up files?

$500 is just the annual failed disk replacements in a good year if we're lucky, in one three server farm I run.

Kinda need some scale here to answer the question better.

 

[Let'sgoflying!]

When you say "server" do you mean a real server (hardware raid, rack mount, dual power supplies, etc...) or just a desktop class machine sitting under a desk "serving" up files?

It is an HP ML350-T09 tower server. The spec pdf - caution, direct link to pdf - says somewhere between 500 and 1400W but I don't know how to tell which it is. It is RAID 1, dual power supplies.
In addition there is the managed switch, the firewall, the modem which will need protection.

 

[denverpilot]

Ahhh the good old Compaq stuff turned HP! (Grin...) That stuff is a tank and should run a long time. It's a few generations old by now, but if it is doing the job, it'll last virtually forever.

The reason the spec sheet can't tell ya is because it can be ordered in multiple configurations. Drives add to the power it needs and it can have different drive cages, can be had with and without hardware RAID, even the average room temperature will change the power draw because the fans are variable speed depending on internal temperature and go faster or slower even depending on CPU load. Etc.

Two possibilities:

- Rate the UPS for the max power draw.
- Measure with a clamp on AC ammeter on all of the power leads, assuming no configuration changes will be occurring and/or padding the result for future disk expansion if it isn't full yet.

The spec sheet does show that three options were available for the power supplies: 500W, 800W, or 1400W max. You may also want to pull one and look at see which type you're using.

An interesting side note: If it's in an air conditioned room or server room, keep in mind that when the site loses power it also typically loses cooling, and anything on UPS is now an excellent room warmer... We've been discussing this problem for one of our small office server closets... Can plan to keep things running for a while, but they're going to need power for the PCs that access those servers also, and not to forget to rate the genset that will probably demand, to run the server room A/C, and wire it into the transfer switch setup... Always something...

 

[Let'sgoflying!]

I have found that I have two 500W power supplies. Presumably the server will actually draw less.
I only need it to run long enough for it to shut down. Staff wont need time to finish work, as the workstations do not have UPS.

 

[denverpilot]

So essentially just pick any UPS vendor and look at their run times for your max load and choose what you like and then check to make sure their shut down software works with whatever flavor of server OS you're using. Some use network some use USB.

Also remember to go into the BIOS and set th server to power back up after a power loss.

Nothing is perfect. If you have a bunch of power outages back to back the server may attempt to boot up against a weak UPS and still drop anyway. Only way you can stop that is something way fancier that kills power to the server at the power strip and locks it out until the UPS system has enough power or is overriden by a human.

We had UPS power during our recent blizzard but the frequency and length of the outages with power going on and off soon led to a server closet with just random things being rebooted all afternoon depending on which UPS hadn't had enough time to charge. Thus the desire to generation power that closet and add the A/C.

 

[weilke]

I have found that I have two 500W power supplies. Presumably the server will actually draw less.
I only need it to run long enough for it to shut down. Staff wont need time to finish work, as the workstations do not have UPS.

It draws a lot less under most circumstances. I believe I have a 1000VA unit and when I test it. it can run two servers for more than 100minutes.

 

[Let'sgoflying!]

My two 500 power supplies are actually redundancies; I don't think it is equipped to provide 1000W. I think the way it is set up is that if one fails, the other takes over. So, if I have it right the very max the server will theoretically draw is 500W.
Sound right?
Plus, the peripheral items...which are probably 10W or something miniscule.
Run time needed; 10 minutes max - ie enough to shut down.
Hopefully I can set it to not start up again for 60 minutes, the typical max storm length. I would not be happy if it automatically restarts in 5 mins.

 

[weilke]

My two 500 power supplies are actually redundancies; I don't think it is equipped to provide 1000W. I think the way it is set up is that if one fails, the other takes over. So, if I have it right the very max the server will theoretically draw is 500W.
Sound right?

It is even less than that. Those power supplies are capable of drawing 500W under maximal load. Unless you are trying to crack the I-phone encryption or process videos, your server is going to be idling with the cooling fans on low and power draw a fraction of the rated number. I can look up on Monday what my servers draw (the UPS shows the power draw). They draw a bit more while booting but once all the power-saving features kick in, they really drop off.

 

[denverpilot]

My two 500 power supplies are actually redundancies; I don't think it is equipped to provide 1000W. I think the way it is set up is that if one fails, the other takes over. So, if I have it right the very max the server will theoretically draw is 500W.
Sound right?
Plus, the peripheral items...which are probably 10W or something miniscule.
Run time needed; 10 minutes max - ie enough to shut down.
Hopefully I can set it to not start up again for 60 minutes, the typical max storm length. I would not be happy if it automatically restarts in 5 mins.

Actually unless the UPS went all the way dead (I wasn't clear on this before) it won't restart at all. Someone will have to start it back up. Once the UPS's add on software (or in the case of Linux, an open source tool) shuts the machine off, it isn't coming back.

HP makes their iLO ("integrated lights-out") devices for doing this remotely across a network, as an option on their servers, or you could use something that would truly interrupt the power between the UPS and the server like a remote power strip that's switchable, and have the BIOS setting as mentioned above.

All of which is overkill if someone can just walk in and turn the thing back on once the power is stable again.