Process "mdworker" Writes to Disk Every 10 Seconds

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Level 2

210 points

Process "mdworker" Writes to Disk Every 10 Seconds

I noticed disk activity occurring every 10 seconds while my computer was idle. In Activity Monitor I could see this writing going on and at the same time the process "mdworker" would tick up just a little bit of processor activity. A Restart didn't help. The following is what I did to make it stop. I've seen many posts on here with a similar problem so maybe this info will be helpful to someone.

I brought up a Terminal window and entered the following command:

sudo fs_usage -w -f filesys

That will show youa continuous list of all processes that are reading/writing to disk (use Control-c to make it stop). I found mdworker doing a fair amount of disk activity every 10 seconds. But the important thing is that it was the identical activity every 10 seconds, and the common thing in almost every entry was "Default Folder X". So I concluded that it was having trouble indexing something about Default Folder's data. (mdworker is used to index your data via Spotlight.) After uninstalling and reinstalling Default Folder, the constant writing stopped and has yet to happen again.

If you're having a problem similar to this you may find this method of identifying the culprit and fixing it useful.

Mac OS X (10.6.8), MacPro V8 (2008), 500GBx2 RAID0

Posted on Jul 16, 2011 5:00 AM

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Answer 1

Jul 16, 2011 6:41 AM in response to Wingsy

Go to the system console and see if there are any messages related to mdworker or mds that say "throttling respawn", which repeat every 10 seconds. If so then let us know what they are (copy and paste them here).

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Answer 2

Wingsy Author

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210 points

Jul 16, 2011 8:17 AM in response to Topher Kessler

I found several messages with "respawn" in them, like this one:

Jul 16 08:02:34 MacProV8 com.apple.launchd.peruser.501[152] (com.apple.pbs): Throttling respawn: Will start in 10 seconds

I found about 4-5 respawn messages per day, going back for about a week. None that I see have mdworker or mds mentioned. I see quite a few messages about mdworker associated with a restart, mostly about a missing this or a missing that. I see them also on a restart after reinstalling DefaultFolder and having the recurring disk write no longer present, so that doesn't seem to be related to it.

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Answer 3

Jul 16, 2011 8:31 AM in response to Wingsy

You can try resetting Spotlight and having mdworker re-index the drive. To do this, just add your drives to Spotlight's privacy list, and then remove them. They should then re-index, and hopefully not require as frequent updates.

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Answer 4

Wingsy Author

Level 2

210 points

Jul 16, 2011 9:37 AM in response to Topher Kessler

I tried that and it had no effect. It was back to doing its thing every 10 seconds once the indexing was finished.

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Answer 5

May 22, 2012 12:13 PM in response to Wingsy

Did you manage to solve this? I have the same/a similar issue.

There are two mdworker processes running and one of them is writing about 15 MB/s every 10 seconds. I know it's this process since the spike in disk write is happening in conjunction with the processes taking some more % CPU power. If I quit this instance of the mdworker process the disk write spikes goes away for about a minute, but then the troblesome mdworker process comes on again and the I'm back to square one.

I've tried to rebuild the Spotligth index and disable search on all drives except my main one.
Only way to get the diskwriting to stop is to disable Spotlight and quit the mdworker processes.

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Answer 6

Wingsy Author

Level 2

210 points

May 22, 2012 1:00 PM in response to star-affinity

Did you do

sudo fs_usage -w -f filesys

in a Terminal window to see what was doing all the writing?

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Answer 7

May 23, 2012 1:22 PM in response to Wingsy

I've done it now, but don't really know what to look for?

If I search for ”write” in the long results that I got after 30 seconds I hit these processes: mds, loginwindow,

lssave (which I can't find as a running process?) SFLSharedPrefsTo (also not a process I guess),

launchd and com.apple.securi.

Any ideas?

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Answer 8

Wingsy Author

Level 2

210 points

May 24, 2012 1:50 AM in response to star-affinity

I'm afraid I don't. The SFLSh... and the com.apple look suspicious to me but I'm not familier with them. Hopefully someone with experience here can chime in and help.

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Answer 9

WZZZ

Level 6

13,220 points

May 24, 2012 5:26 AM in response to star-affinity

Try this, courtesy of Baltwo. It will delete the Spotlight V-100 index and then force Spotlight to re-index.

Be absolutely certain to only copy/paste these commands exactly. DO NOT try to type these in.One typo or wrong space in the first one could wipe your drive competely. Hit return after each.

Delete the entire Spotlight directory and reindex, running these commands in the Terminal app:

*sudo rm -R /.Spotlight-V100*

*sudo mdutil -i on /*

*sudo mduitl -E /*

https://discussions.apple.com/thread/2733259?answerId=12988300022#12988300022

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Answer 10

May 24, 2012 5:28 AM in response to WZZZ

Than's so much for trying to help, but I've already tried doing this – resetting Spotlight and letting it re-index.

I could of course try one more time and see, but I'm afrain the problem is somewhere else.

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Answer 11

WZZZ

Level 6

13,220 points

May 24, 2012 5:32 AM in response to star-affinity

Did you first delete the .SpotlightV-100 ? How did you remove and then reindex Spotight? Through Terminal or the Finder?

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Answer 12

May 24, 2012 5:38 AM in response to WZZZ

Did it through the Terminal, and yes – I deleted .Spotlight-V100.

Also tried using the software Cocktail: http://maintain.se/cocktail

But I'll absolutely try again using the Terminal commands above, and we'll see. Will get back witht he results.

Thanks!

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Answer 13

May 24, 2012 10:47 AM in response to star-affinity

By the way, there is a typo on the last command. It says mduitl instead of mdutil.

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Answer 14

WZZZ

Level 6

13,220 points

May 24, 2012 10:55 AM in response to star-affinity

Yes, thanks for catching that.

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Answer 15

May 24, 2012 11:58 AM in response to star-affinity

OK, I did the reset of Spotlight and had it re-index. No go same 16 MB/s peaks every 10 s.

I have a clone of my drive with OS X that is a few months or so old. When I start up from that I don't get this peaks, so it must be something that happened after that. I have no idea what, though. 😟

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