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Is ML Power Nap also running on Mac Pros?

DanielCoffey

DanielCoffey

macrumors 65816
Original poster
Nov 15, 2010
1,208
30
Edinburgh, UK
I was wondering if something like the Power Nap that is supposed to be limited to the MacBook Air and Retina MB Pro is running on our Mountain Lion desktops?

The reason I ask is that since updating to ML, I have noted two occasions where my Sleeping MP 5,1 has half woken up for about 10s (fans, USB Power but NOT monitor), done whatever it wanted to and then gone back to Sleep.

Pressing a key while it is in this half-awake state does not wake it up fully. I have to wait till it is done and then wake the MP up.

I also noted that immediately on waking, the New Mail notification (top right) was present even though my internet connection would have taken a couple of seconds to poll for mail after waking.
 
Power Nap is limited to computers that come with SSDs standard and have the firmware update. So, no Mac Pros don't have Power Nap. Network activity might be a likely cause for your Macs waking up though.
 
Well it never did it under Lion during the past year but I have seen it twice in the past week while I have been at the desk since upgrading to ML so I wondered.

I do have an SSD boot drive, but I know it was supposed to be limited to the newer MacBooks.

OK, next question... how do I find out from logs what triggered the half-wake-up then?

It was long enough for an internet connection to be established and for Mail to poll - around 10 seconds I would say but the screen didn't come on. I also noted the time it occurred... 07:30 local time to the second.
 
I now have some more information about this "Power Nap" behaviour on a Mac Pro under Mountain Lion 10.8.0...

While my 5,1 is in Sleep mode, it will partially wake up at very specific times - 01:30, 04:30 and 07:30. I can verify this and it is predictable to the minute. The screen is always dark but the fans spin up for about ten to twenty seconds.

When I manually wake the machine afterwards, there is often an instant notification that I have new mail then another notification about five seconds later once the net connection is established and the mail server is polled. The first notification occurs because the machine partially woke during the night to check for new mail.

While I don't mind the behaviour too much I would really like to know if it can be disabled because it is distracting to have the machine click on during the night and I would particularly like to know what process is triggering to wake the machine. If I can prove it is an Apple process, I can relax a little. Until then, my imagination will dream up a whole host of implausible and crazy tinfoil-hattery reasons for it to be happening

Are there any logs that will tell me what activity was taking place on the machine at a given time?
 
OP, judging by symptoms, this is waking your MP:

Apple uses the service with its Airport Base Station or Time Capsule devices, which act as a "Bonjour Sleep Proxy" that registers the device and allows it to be accessed when it is asleep. When you try networking with the device when it is sleeping, the proxy will issue the magic packet to wake it up and allow you to access it.

Even if you do not have a sleep proxy on your network, the Mac may still be woken if a magic packet is sent to it, and it will also periodically wake briefly in an attempt to register with a sleep proxy. This behavior is historically enabled on Ethernet devices, but on newer Macs you can use the Airport connection for this option as well. To prevent this behavior, you can disable the WOL feature by unchecking "Wake for network access" the Energy Saver system preferences. If your system supports WOL over Wi-Fi only, then you will see this called "Wake on Airport network access," and if it supports WOL on Ethernet only, then you will see "Wake on Ethernet network access."
Click to expand...

Source: http://reviews.cnet.com/8301-13727_7-57333182-263/tackling-macs-that-randomly-wake-from-sleep/
 
Thank you for that Terminal command, Paul.

I checked and the reason code was "Wake Reason: RTC (Alarm)"

The page you linked suggested that may be a Wake On Demand service such as Energy Saver sleep or wake events but none of those events were in the Schedule.

Googling "mac wake reason: RTC (Alarm) 10.8" lead me to a page where someone had the issue in Lion when they had Wake on Network Access ticked.

They had the same symptoms of a wake from sleep of the entire machine except the monitor. They gave a link to the Apple Knowledgebase article on Wake On Demand which effectively said that any recent Mac will attempt to poll the Bonjour Sleep Proxy service at regular intervals to advertise its shared services whenever Wake on Network Access is ticked.

The method to disable it is to un-tick Wake on Network Access.

I did notice that Wake on Network Access was ticked so I un-ticked it since I am the sole user on this network. I guess I must have un-ticked it when I had Lion and it probably defaulted to ticked when I upgraded to Mountain Lion.

Problem solved.

+1 to Paul, thanks.

----------

666Sheep - yes, you were correct. I was typing that lot while you replied.

Once again, thanks folks - it is solved!
 
Yes, I understand - I only referred to it as behaving like power nap since I knew it was a new feature that should not have been active on a MP.

As you will see from the above replies, the issue has been identified and resolved.
 
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