Hard disc constantly writing

Question

Level 1

10 points

Hard disc constantly writing

The hard disc on my iMac is writing constantly. I cannot see any processes in the activity monitor which indicate anything odd going on. Any ideas anyone?

iMac, Mac OS X (10.6.5)

Posted on Dec 31, 2010 5:31 AM

Reply

Answer 1

baltwo

Level 9

62,362 points

Dec 31, 2010 12:24 PM in response to rowanyarn

Select All Processes and click on Disk Activity. During normal operations, such as composing this post, shows intermittent write spikes in the graphic, but no constant writing. Do note that %CPU always shows constant processes running.

Reply

Answer 2

Jan 3, 2011 12:17 AM in response to rowanyarn

Hi,

I've noticed this, too, since the middle of December. When I look at Disk Activity in my Activity Monitor, I see a disk write of 1.6 MB about every 10 seconds. This coincides with a spike in processor usage by an mdworker process owned by my username.

If I force quit the mdworker process, the disk writes stop until the process shows up again. I also see it in the Terminal application if I run this command:

iostat -w 1 disk0

The output looks like this:

disk0 cpu load average
 KB/t tps MB/s us sy id 1m 5m 15m
 34.04 237 7.86 3 1 95 0.00 0.05 0.12
 0.00 0 0.00 0 0 100 0.00 0.05 0.12
 0.00 0 0.00 1 0 99 0.00 0.05 0.12
 0.00 0 0.00 1 0 99 0.00 0.05 0.11
 0.00 0 0.00 0 0 99 0.00 0.05 0.11
 657.60 5 3.21 0 0 100 0.00 0.05 0.11
 0.00 0 0.00 0 0 100 0.00 0.05 0.11
 0.00 0 0.00 1 0 99 0.00 0.05 0.11
 0.00 0 0.00 0 0 100 0.00 0.05 0.11
 0.00 0 0.00 1 1 98 0.00 0.05 0.11
 0.00 0 0.00 0 0 99 0.00 0.05 0.11
 0.00 0 0.00 0 0 100 0.00 0.05 0.11
 0.00 0 0.00 0 0 99 0.00 0.05 0.11
 0.00 0 0.00 1 0 99 0.00 0.04 0.11
 0.00 0 0.00 1 0 99 0.00 0.04 0.11
 657.60 5 3.21 0 0 100 0.00 0.04 0.11
 0.00 0 0.00 0 0 99 0.00 0.04 0.11
 0.00 0 0.00 1 0 99 0.00 0.04 0.11
 0.00 0 0.00 0 0 100 0.00 0.04 0.11
 0.00 0 0.00 1 0 99 0.00 0.04 0.11
 disk0 cpu load average
 KB/t tps MB/s us sy id 1m 5m 15m
 0.00 0 0.00 1 0 99 0.00 0.04 0.11
 0.00 0 0.00 0 0 100 0.00 0.04 0.11
 0.00 0 0.00 0 0 100 0.00 0.04 0.11
 0.00 0 0.00 1 0 99 0.00 0.04 0.11
 0.00 0 0.00 1 1 99 0.00 0.04 0.11
 657.60 5 3.21 0 0 100 0.00 0.04 0.11
 0.00 0 0.00 1 0 99 0.00 0.04 0.11
 11.85 13 0.15 1 1 98 0.00 0.04 0.11

Again, the spikes coincide with an increase in processor use by mdworker. The spikes here are at 3.21 MB/s, presumably because the update time is different from Activity Monitor. If I use a 2 in the Terminal command, the updates are two seconds apart and iostat output is, as expected 1.6 MB.

I've turned off Spotlight indexing on my hard drive for now, and killed the mdworker process. I'm no longer seeing the regular writes. I'll let it go overnight and see what it looks like in the morning.

Here's a graph that illustrates the increased writes (red is write, green is read):

charlie

Message was edited by: Charles Minow

Reply

Answer 3

Jan 3, 2011 6:22 PM in response to Charles Minow

Just reporting back with the results of my experiment: in my case it's the mdworker process. My iMac is back at more normal levels of disk writes for the last 18-20 hours once I disabled Spotlight indexing on the main hard drive and killed the mdworker process owned by my account.

charlie

Reply

Answer 4

baltwo

Level 9

62,362 points

Jan 3, 2011 10:53 PM in response to Charles Minow

Interesting. I've not disabled mds or mdworker and see little or no writing with it.

Reply

Answer 5

TZW

Level 1

54 points

Feb 1, 2011 1:43 PM in response to rowanyarn

I have the same problem since this morning. The hard drive sounds like a pop-corn maker.

I have tried restarting, turning off Spotlight, running Coctail Pilot, running Disk Utility, force quitting mdworker, logging in with a new user account...

I see nothing odd in Activity Monitor or Console (but I'm not very familiar with those apps).

What could this be about? Could it be a faulty hard drive and not a software problem?

Reply

Answer 6

RobBT

Level 1

81 points

Feb 2, 2011 1:21 AM in response to rowanyarn

Hi,

Same problem here.

For the last, say, three weeks I think my HD is too busy reading and writing. I don't think I heard so much activity before, while I do recall thinking my MBP was really very silent.

There is disk activity almost all the time.

CPU usage is normal for all processes, mds and mdsworker show normal activity (no Spotlight problem).

Scrutinizing the Console Messages didn't give me any clue either.

(No sound or signs of HD failure by the way.)

What should I look for? And where? Anyone?

Reply

Answer 7

TZW

Level 1

54 points

Feb 2, 2011 11:53 AM in response to RobBT

This is really annoying. I've had this Mac for months and it's been silent until yesterday - since then, constant hard drive activity. The sound drives me crazy! And since the drive is busy all the time, the computer never goes to sleep. I guess I should reformat the drive and see if that helps, but I have work to do :/

Reply

Answer 8

satcomer

Level 4

1,539 points

Feb 2, 2011 2:46 PM in response to TZW

Try to exclude the hard disk in Spotlight's System Preferences to see if that helps.

Reply

Answer 9

TZW

Level 1

54 points

Feb 2, 2011 11:26 PM in response to satcomer

Thanks, yes I already tried that. Doesn't help, except the writing stops for a short while when I turn Spotlight back on.

Message was edited by: TZW

Reply

Answer 10

TZW

Level 1

54 points

Feb 8, 2011 10:07 AM in response to TZW

I did finally get the time to format my drive and reinstall everything. Result? Better - it still sounds as if the drive is constantly writing, but the sound is more quiet. Now I have to lean in towards the display to hear it. It was much louder before. This is quite odd. If it was easier to replace the drive in the 27" iMac I would try another brand (my drive is a ST31000528AS).

Message was edited by: TZW

Reply

Answer 11

RobBT

Level 1

81 points

Feb 9, 2011 2:35 PM in response to rowanyarn

Anybody out there who can tell how to find the app that's causing all the disk activity?

Anybody who can explain what amount of hard disk read and write is normal? (Not talking about a defective HD here.)

Anybody not mentioning Spotlight issues? Spotlight is not the culprit here.

I would be grateful when pointed in the right direction. The almost continuous soft rattle of my MBP's hard disk is getting stuck in my brain like a bad song on the radio.

Reply

Answer 12

TZW

Level 1

54 points

Feb 10, 2011 2:01 PM in response to TZW

The constant writing slowly picked up again until it drove me crazy once again :-/

But I just ran sudo fs_usage in Terminal and found lots of references to Adobe Version Cue. So I popped in my CS3 DVD, uninstalled Version Cue, restarted and - fingers crossed - my hard drive has been quiet now for the last ten minutes... and no data is written to disk (Activity Monitor).

Reply

Answer 13

jkrutch

Level 1

0 points

Aug 18, 2011 11:35 AM in response to TZW

I have a 27" Core i7 2.93 1TB iMac with the constant hd issue as well. Found this thread, ran the sudo fs_usage command and found Mail to be the cultprit. Here's the kicker....I followed the path to the problem and it doesn't exist. Here is part of the path: .... /117E45F2-E840-43ED-8957-0C208A255FB9/Data/5/0/1/Attachments...

I was able to get to the mailbox path above, but the path ends at the zero. On my HD, nested after the "...data/5" in the path is a folder named "7". There is no 0/5/1/Attachments....

Any thoughts on finding the missing folder? Already ran Disk Utility and repaired all permissions, etc.

Thanks in advance.

Jon

Reply

Answer 14

rjf1

Level 1

0 points

Aug 24, 2011 12:10 AM in response to rowanyarn

Hi,

Maybe just a wildcard answer as I know nothing but I had this problem too.

Only after a reinstall, and the noise started again did I discover the "LaunchAgents" folder in the Library.

There were some .plist files belonging to trial software I no longer used - after removal things are back to normal - it seemed to turn the popcorn maker off!

WARNING!!!! I'm old enough to know better than recommend people tinkering around in the library don't blame me if you didn't back up and ended up deleting the wrong files... I'm just passing on what solved the issue for me.

Kind regards

Reply

Answer 15

Kdapple

Level 1

0 points

Aug 25, 2011 11:43 AM in response to rjf1

I'm having this problem as well. I've narrowed it down to PubSubAgent. If I kill that process, the activity stops, otherwise it seems to be constantly writing to my disc at atleast 1.3MB / sec often with higher spikes. This apparently has something to do with updating RSS Feeds etc. Any idea how I can figure out what apps are using this?

This is what it is meant to do: The PubSub agent syncs the RSS read/unread status of bookmarked RSS feeds between computers using Mac OS X 10.5 that are syncing bookmarks via MobileMe Sync.

I don't use MobileMe.

Reply