sleeping hard disks and time machine - problem?

Glenn Leblanc wrote:
I don't know why you're getting those (improper device removal). Putting your computer to sleep should not eject the drive and it should not be ejecting itself while sitting there.

I believe the macbook depowers the USB port upon sleep if running on battery.

If you are using Time Machine then do not let the computer sleep. Have it connected to the AC adaptor and configure Energy Saver preferences for the Power Adaptor to not sleep and turn off the option to put the drives to sleep when idle.

Backups should never be done while on battery power.

No, it's a problem on any computer. TM needs to have access to the drives every hour, and it the computer goes to sleep when TM is running, then TM stops running. TM also does not automatically wake up sleeping drives which again interferes with the backup process.

Furthermore, backing up on battery is dangerous to the security of your backup if the computer has to shut down.

Just because you have friends that do something doesn't mean they know what they are doing.

TM will continue when the machine wakes up but then it no longer will backup on the same hourly schedule.

The improper device removal will happen if the drives are allowed to sleep on idle or if you fail to eject an external device properly.

Hi Kappy

I'm a little confused about never letting your computer sleep and not letting hard drives sleep because of TM. I could understand about not letting it sleep on the initial backup just to avoid problems, but I've never seen anything suggesting not letting the computer sleep because of TM.

This is from the TimeCapsule setup manuel: "If you shut down your Mac or put it to sleep during a backup, Time Machine stops the backup and then continues from where it left off after your Mac starts up again." That surely doesn't suggest any problems using sleep mode from Apple.
I understand that it will change the exact times backups will run from there, but why would that be important. It will still run every hour from that point after.

Even though it doesn't hurt to leave the computer run 24 hours a day, what's the point of letting it attempt to backup hourly when your not even using the computer. Sleeping the computer gives everything a rest and hard drives won't be spinning up and down while your sleeping at night or away from the computer for longer periods of time. If your on it all day, it may be best not to let it put the computer & hard drives to sleep. But if you have no need for it to be running, at least manually sleeping it at the end of the day would make great sense to me. Just to save power if for no other reason.

I also would understand about using an external drive that would show a warning of improper ejecting because of sleep. That would not be a good thing if the drive were ejecting because of the computer going into sleep mode and probably would cause problems.

I have used an external Lacie Quadra 2 with firewire 800 on this computer for a year now with TM. I never shut my computer down, but I have always had my computer set to sleep after an hour of inactivity and sleep hard drives when possible. I have never had a single issue with TM backing up properly or giving any trouble.
However, I never get messages about the external drive not ejecting properly because of sleep mode. When it wakes, it still sitting there mounted like before. So that point is not an issue for me.

I also have another iMac set up the same way with TimeCapsule as a network drive with ethernet. It's been up and running for 3 months and never has a issue with TM either. Backups are performed hourly when awake & stays idle when computer is sleeping.

I know your very knowledgeable about Macs (far more than me), but like I said, I just didn't understand that point.

It may be that he disk is failing. I've had thsi problem over the last couple of weeks, with the disk "ejecting improperly" more and more frequently. Now it just sits there and clicks and flashes its access light, but the computer can't "see" it and it's dead, basically.

I don't know why you're getting those (improper device removal). Putting your computer to sleep should not eject the drive and it should not be ejecting itself while sitting there.

I would not trust or use it for any backup if until the problem is found and fixed it's fixed or replaced.
It could be a USB or compatibility issue. Try it on a different USB port and a different USB cable.
If your friends have a Mac, you could try it on their computer to see if it ejects when their computer is put to sleep. Then you will know if it's a drive problem or a software issue on your Mac.
Someone with more knowledge about that drive will need to advise you.

USB drives are great, but I like the firewire 800 drives more for my backup drives. They are faster and for me have been more reliable.

My click-of-death WD portable drive works perfectly when plugged into a Win7 box...but still just goes click-click-click in an iMac 😟

What's that about??

It could be your usb port on your computer is going bad, but I don't know. Try other USB devices there to see if it functions OK.

You should start your own thread. You will be more likely to get help to solve your problem.

Kappy wrote:
TM also does not automatically wake up sleeping drives which again interferes with the backup process.

Perhaps you mean something else by sleep, but if you're using the "popular" notion, you are absolutely incorrect here. TM will, in fact, wake up a sleeping drive to perform backups. I have verified this on multiple occasions over the past 2+ years (and just now), and have regularly been allowing Mac OS X to sleep my external hard drives. I have never received an improper ejection error notice, and I have never had a failed TM backup.

On waking, TM checks to see if a backup has been performed in the past 60 minutes, I believe. If one has, it will not initiate a backup (e.g. you perform a backup at noon, sleep the computer at 12:15, wake at 12:45). If, however, the computer has been asleep for more than an hour (same scenario, but you wake the Mac at 2p), TM will initiate a backup. This can be disabled with 3rd-party apps, byt the way.

It is also quite alright to sleep a computer in the middle of a TM backup. I do it all the time on my laptop. TM will pick back up when you wake again (if it was "cleaning," for example) and will determine on its own if a new backup needs to be performed. On multiple occasions, I have witnessed a backup that was interrupted mid-way by a system sleep perform a quick check and then restart the backup where it left off, combined with any changes in the intervening period.

By the way, the above applies to a physical external hard drive, and may not apply to a sparsebundle backup.

The advice about backup up on battery is also incorrect. An issue arises only if the charge is insufficient. An incremental backup on, say, 90% charge is fine. It would not be advisable on 10%. That being said, as long as it is not the external drive that loses power, TM will just resume once power is restored to the Mac. If the TM drive loses power, corruption could occur.

Just because you have friends that do something doesn't mean they know what they are doing.

Always good advice, but it doesn't mean they don't know what they're doing...

You are fine to let the computer sleep. And for all his excellence with respects to Macs, I believe Sleepy is wrong here. What you're likely experiencing is that your MacBook is killing the power to the USB port on sleeping (to save battery life). If you're driving the external drive from the USB port alone, a loss of power would result in an improper eject. If, however, you can keep the external drive plugged into an external power source, you shouldn't have that problem. I think if you leave the Macbook plugged in, it will continue to supply power to the USB port after sleep (based on my experience charging an iPhone).

Bottom line:

Macbook on battery = USB port unpowered during sleep = improper removal
Fix: plug in external HDD to independent power source

Macbook on AC = USB port powered during sleep = no issue