Mysterious disk writes

G

guyeva

Registered
I recently added another 2tb Western Digital MyBook external USB drive to my PowerMac MDD, the sixth such external drive on my system, and I'm seeing some strange behavior from it that I have not observed at all with the other drives.

It's little white light flashes a lot, on and off, when I'm not writing anything to it or reading anything from it. So I start up Activity Monitor, and I'm seeing writes to disk and reads from disk as that light flashes when I'm not doing anything at all on disk, which I find most curious.

Now I can see that there would be a certain amount of device polling going on, and that makes sense, but what is being written to that disk when I'm not even using it, and what's doing those disk writes? I have no idea, and it appears to be happening on this new drive, but not the others, and I can't imagine why. There are about 700 movies on that drive, but no program files at all.

This is pretty weird. Anyone know what might be going on?
 
So - you have 5 other WD 2TB drives attached through USB, and that's the only one that does those intermittent read/writes?

Perhaps there's some change in the firmware on the new drive?
Are all your externals formatted as MacOS Extended volumes?
Is that new drive your only storage for those movie files - and is anything else stored there?
Are those movies ever modified or edited after you store them on that drive?
There's usually a time/date associated with writing files to the disk.
Have you looked for files that get written? Might be good to know the name of new files. That might help determine what is creating them (if any). And, files could be normally hidden, so if you don't see anything, be sure to make all hidden files visible while you look around.
If you are not sure how to do that, a variety of utilities will let you do that, such as TinkerTool, or OnyX.
 
guyeva said:
I recently added another 2tb Western Digital MyBook external USB drive to my PowerMac MDD, the sixth such external drive on my system, and I'm seeing some strange behavior from it that I have not observed at all with the other drives.

It's little white light flashes a lot, on and off, when I'm not writing anything to it or reading anything from it. So I start up Activity Monitor, and I'm seeing writes to disk and reads from disk as that light flashes when I'm not doing anything at all on disk, which I find most curious.

Now I can see that there would be a certain amount of device polling going on, and that makes sense, but what is being written to that disk when I'm not even using it, and what's doing those disk writes? I have no idea, and it appears to be happening on this new drive, but not the others, and I can't imagine why. There are about 700 movies on that drive, but no program files at all.

This is pretty weird. Anyone know what might be going on?
Click to expand...

This sounds like Spotlight Indexing. Nothing to be concerned about. If it is bothersom you can disable Indexing that drive or disable spotlight all together.
 
DeltaMac said:
So - you have 5 other WD 2TB drives attached through USB, and that's the only one that does those intermittent read/writes?

Perhaps there's some change in the firmware on the new drive?
Are all your externals formatted as MacOS Extended volumes?
Is that new drive your only storage for those movie files - and is anything else stored there?
Are those movies ever modified or edited after you store them on that drive?
There's usually a time/date associated with writing files to the disk.
Have you looked for files that get written? Might be good to know the name of new files.
Click to expand...

Well, I also considered a possible firmware change in the new WD drive, but I have no way of verifying that. This is the only drive out of six that I've seen this behavior with, and it's the most recently added, so that might be the case.

Yes, all my external drives are formatted the same, MacOS Extended.

Yes, that new drive is the only location for those particular movie files, and they are never altered or modified, they are .avi, .divx, .mp4 files.

Yes I have looked for new files written to that disk, and there are none that I can see. The number of files in finder has not changed either. I'm quite mystified here.

This is what I see happening in Activity Monitor:

http://i252.photobucket.com/albums/hh3/vaslovik/Weirddiskwrites.jpg
 
Activity monitor showing only your processes, is pretty meaningless.
Click the dropdown, and change My Processes to show All Processes.
Are you checking Activity Monitor at the time that you see the activity light on that hard drive?

Did you show hidden files, then look at that hard drive for changed files?

If you really don't see anything amiss, and the performance of that drive is not affected, then ...

Are you SHARING files on that hard drive? Check in System Preferences/Sharing pane.

You could also EXCLUDE that drive from Spotlight, to see if that's the issue. (System Preferences/Spotlight/Privacy tab. Add that drive to the list.) If the drive activity essentially stops, that's your issue.
 
read this on your MacRumors post. Seems to me that it is Firefox taking up the most resources instead of iTunes. Follow these steps to disable Spotlight.

Disabling Spotlight
To turn off Spotlight in Leopard, use this trick:

Move these two files to another safe location and then reboot your mac

/System/Library/LaunchAgents/com.apple.Spotlight.plist

/System/Library/LaunchDaemons/com.apple.metadata.mds.plist

Re-enable Spotlight by moving those files back to their original location, reboot, and Spotlight will work again.
That’s pretty much it, on your next reboot, Spotlight will be completely disabled.
 
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Okay, I switched to all processes, but I can't figure anything out from that. I'm not sharing any files at all, there's no network here. I did exclude that drive from Spotlight though, and I'll be watching it for a while to see if that stops the unknown writes.

Thankee much :)
 
guyeva said:
Okay, I switched to all processes, but I can't figure anything out from that. I'm not sharing any files at all, there's no network here. I did exclude that drive from Spotlight though, and I'll be watching it for a while to see if that stops the unknown writes.

Thankee much :)
Click to expand...

Spotlight has nothing to do with file sharing. Spotlight is used to search the computer for files. If you ever used Panther Spotlight used to be called Sherlock. This changed to Spotlight in Tiger.
 
Okay, excluding that drive from Spotlight has not stopped the problem, and I have no idea what else it might be. I've asked my dog, but he doesn't seem to know either. We are both pretty baffled here....
 
The dog said your cat did it.

Sharing does not mean that you are connected to a network - (just makes more sense that way) - I was really asking you to look in the Sharing pane to check if you had some part of sharing turned on, that was supporting your newest hard drive (and no other hard drives.)
Another question - How long have you been using this new hard drive? A few hours, several days, more than a month?
Have you run Disk Utility/Repair Disk on that hard drive (NOT Repair Disk Permissions)?

In your Activity Monitor/All Processes - sort the window by CPU, so busy processes will be listed at the top. Notice when the activity light gets more busy, and note the top of the list. You could post the top 5 or 6 to see if someone here will give you a clue about what is really happening, especially if one or two of those ONLY appear when the activity light is flashing. Some flash in and out pretty quickly, so that may not be easy to see.
But, could simply be a firmware difference, with no performance hit, and no harm - and not for you to worry about - try ignoring the light for a few days. Maybe that's needed, and the hard drive will then start acting like your others.
 
Ummm... we don't have a cat. Buddy the noteworthy dog does not want a cat living here, nor do I since the last one had a habit of walking on my keyboard and was no help with computer issues.

Okay, the sharing thing, I'll check into that, and thanks for telling me about it. I'm not a real Mac geek at all, and I'm still finding all this stuff out. It's not easy being stupid.

I've had this drive about a week now and I set it up with the disk utility after the WD software crashed on me as soon as I tried to use that. Apparently WD Smartware doesn't like old G4's running Leopard. I'll check into repair on that drive, but it doesn't seem to me like a brand new drive that was just set up would need repair.

I've already noted that the programs using the most CPU tend to flash in and out pretty fast and you are right, it's not easy to connect them with the disk light flashing or the disk activity in Activity Monitor. This morning the light on that disk is just slowly flashing on and off at regular intervals, and again this is something none of the others have done. Perhaps the drive is haunted.

Thanks for your helpful suggestions!

PS: Checked the sharing thing, and nothing is shared on my machine at all.
 
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I'll check into repair on that drive, but it doesn't seem to me like a brand new drive that was just set up would need repair.
Click to expand...
And, that would be the point (it's another item to check).
Open your Disk Utility, choose that external hard drive, then click the Repair Disk button. Don't waste your time with a "Verify Disk" - the Repair Disk also does a verify as part of the process. I'm not assuming there's something wrong with that hard drive, but the Repair Disk is just another step toward helping you be more confident about the status of that hard drive - and you can say "tried that, no problems found!" The Repair Disk hurts nothing in any case, and you might even find out there's a problem with the hard drive.
Even brand new hard drives can fail - there's one reason why you have a warranty!
 
Also take a look at your Mac's log files to see what is going on. Go to /Applications/Utilities/Console and look at the logs after one of these mysterious writes activity. See what is being written.
 
guyeva said:
I've had this drive about a week now and I set it up with the disk utility after the WD software crashed on me as soon as I tried to use that. Apparently WD Smartware doesn't like old G4's running Leopard.
Click to expand...

I never knew WD's software worked on Macs. Than again the last time i bought a Retailed WD HDD i didnt have any Mac systems. And my ceriousity is getting the better of me so sorry for going off topic on this issue but why do you need a HDD that big? both my Macs are using 40GB HDDs and i still have plenty of space.
 
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