[blakespot]

Ever since I got my eCesys 486-66 machine fabricated to run NeXTSTEP for Intel v3.3, I have kept my primary machine on 24/7. Back then when I looked into it the school of thought was that always-on is easier on the hard drives, the fans, and the circuitry of the computer overall as the power-on/ramp-up process is much "harder" on all components involved than just always being on - especially given that there will be several use sessions per day. And it avoided the boot time wait and let me run 33.6Kbps download from the net all-nite. :-)

On this new G5 we're talking about three disks, 9 fans, and a liquid coolant pump. Has the thinking changed in general here? The one variable I'm rather unsure about is the wear on the liquid coolant pump. How do those wear? Same rules as any fan?

NeXTSTEP that I ran back then, and the latest version of that OS that I run now on my G5, OS X Panther, are both UNIX and as such nightly scheduled tasks that are standard can't run when the system is off. UNIX was not designed as a occasionally-on operating environment. I know that we now have "sleep" and that avoids wait time for boot, but still disks and fans must spin up at "wake."

Thoughts from old gurus?


blakespot

[GoGoReggieXPowars]

Frankly I've always been suspicious of the claims of just how much "wear and tear" is caused by power cycling: if you're doing it 10 or 20 times a day, then you've got problems, 2 or 3 I wouldn't even worry about it.

These days, if it's not being used for anything, Sleep it, that's exactly what it's there for. A utility like Onyx can run the Daily/Weekly/Monthly scripts on demand. Even if it's on 24/7, no load on the CPU will take it into low-power mode, making it not use the cooling system or system fans.

[blakespot]

I understand that Sleep mode is there to sleep the machine. Sleep mode is a fairly recent thing for desktops. And its mere presence does not validate the route of powering off / sleeping hardware as being easier on said hardware than constant-on.




blakespot

[tooki]

Yes, it is technically true that hard drives have finite limits of spinup cycles. In practice, though, no normal user comes anywhere close to approaching those limits. As for the claims of the walls of electrons surging through the wiring and chips... that's pure baloney.

In practice, use the machine in whatever fashion is most convenient for you -- for me, that means staying in sleep mode.

tooki

[Big Mac]

To add a few more details, when a modern Mac's power light pulsates during sleep, it means the computer is in "deep sleep." Deep sleep mode is very similar to having the computer off, because most components are turned off and the processor goes into low power mode. The computer has just enough power to maintain the state of RAM and allow the processor to respond to wake commands. There is no reason to keep a modern computer on all the time, since deep sleep is a great compromise between the two states of operation. Oh, if you were wondering about hard drives spinning up too often, you should note that modern computers have their drives set to spin down when not in use. (So obviously there is not a big concern with drive wear.) Of course, the OP is correct about cron tasks (which are scheduled to run in the early morning) not running when the computer is off or in deep sleep. You can remedy that by downloading an app like the freeware MacJanitor. Finally, it is important to consider your electricity usage. G5s are power hungry (just as all high performance workstation computers are), and that is especially true for the DP 2.5.

[Webscreamer]

While having your computer in "Sleep" more at night, will it wake up for the cron tasks to be completely and then go back to sleep, or when in "sleep" they are not done at all?

[OzarkMtn]

Check this out:

Anacron

[Big Mac]

Originally posted by Webscreamer:
While having your computer in "Sleep" more at night, will it wake up for the cron tasks to be completely and then go back to sleep, or when in "sleep" they are not done at all?

Your Mac will not wake up to run cron jobs while it is asleep. That is why I recommended a third party graphical front-end to cron, like MacJanitor.

[Webscreamer]

Originally posted by Big Mac:
Your Mac will not wake up to run cron jobs while it is asleep. That is why I recommended a third party graphical front-end to cron, like MacJanitor.

Well, I never let my computers sleep anyway. Just wondering if i could

[chrisutley]

pbg4:~ chris$ uptime
23:18 up 11 days, 21:59, 2 users, load averages: 0.96 0.55 0.88



I didn't realize how long I've been going between reboots, until I read your thread here. OS X 10.3 is rock solid, baby. Apple has never had this big an edge in the OS wars. I hope they can figure out how to leverage that advantage by translating it into some additional market share and more great innovations.

Of course uptime like this is no surprise to a longtime UNIX user. Nevertheless, Apple should be proud.

I wonder if I should reboot in a couple months, just for the heck of it?

[Webscreamer]

yeah, UNIX is stable and OS X is stable. But when apps crash on me, you CAN'T tell me they don't affect other applications. When one thing crashed, weird **** starts happening and I get the beach-ball from hell. But this only happens when i'm working hard with tons of apps.

So I still restart a couple times a week. But my web server running 10.3.5 server running normal operations can go forever.

[Graymalkin]

Originally posted by Webscreamer:
But when apps crash on me, you CAN'T tell me they don't affect other applications. When one thing crashed, weird **** starts happening and I get the beach-ball from hell.

The crashed apps do not affect other running applications. What does happen is serious memory swaps when an application is forced from memory and things have to be shuffled to and from disk. When something has to wait a while for a page to come out of the swap or wait for the hard disk to spin up to write a crash log you can run into the rainbow beachball. This doesn't mean other applications are affected, simply that the system has to wait for slower aspects of the hardware to kick into gear and get their work done.

The the OP, don't worry about it. There's only a few cron jobs that run on a daily basis and none of them need to run in order for the system to remain usable. If you feel you need to restart daily then go ahead. Old Unix machines weren't designed to be shut off daily, Unix as an OS paradigm is perfectly capable of being shut down on a daily basis if you like to.

However as long as the G5 has decent enough ventilation I wouldn't worry about it much. The hard drives will shut off and any devices not being used to their maximum capacity will be scaled back into "low power" mode automatically. A PowerMac is going to suck more power running at 100% than just sitting idle. I would recommend however you just use the sleep mode. There's a second wait for the system to come back up and be usable but then it is sipping power when you're not around. You get the low power usage benefit of powering the system off with the near instantaneous response of the system remaining powered up.

[OreoCookie]

Well, the G5 can handle 24 h operation. Hell, my company even uses some old-school CRT iMacs as a mail server and they run flawlessly.

Especially the G5 with his cooling system could handle full load 24/7.