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#37162 - 11/13/15 10:50 AM missing gigs of disk space
Virtual1 Offline


Registered: 08/04/09
Loc: Iowa
I've ran into this problem on a larger scale but lacked the time to investigate it. Now I'm seeing smaller examples on a larger scale and have decided to try to figure it out.

These two computers were imaged from the same DMG and have been in use for a few months. Users have their home folder on another partition, allowing me to nuke the OS partition and reimage it without affecting user data. So nothing the (non-admin) users do should be able to make much of an impact on usable space. My having partitioned the drives (SSDs) means I have a hard limit on space on the system volume, and I'm trying to not use more than I have to, so more is available for the user home folders on the other partition.

This computer has 17gb free:

Code:
df -ht /
Filesystem     Size   Used  Avail Capacity  iused   ifree %iused  Mounted on
/dev/disk0s2   93Gi   75Gi   17Gi    82% 19826055 4555238   81%   /

du -shx *
4.0K	 image.txt
 47G	Applications
436K	Creative Cloud Files
4.0K	DeployStudio_log.txt
9.4G	Library
1.0K	Network
5.1G	System
4.0K	User Information
4.0K	Users
2.3G	Users_old
4.0K	Volumes
2.3M	bin
4.5K	dev
4.0K	etc
1.0K	home
4.0K	installer.failurerequests
1.0K	net
1.3M	opt
4.5G	private
1.1M	sbin
4.0K	setup.xml
  0B	t
4.0K	tmp
608M	usr
4.0K	var


This computer has less than 8gb free:

Code:
df -h /
Filesystem     Size   Used  Avail Capacity  iused   ifree %iused  Mounted on
/dev/disk0s2   93Gi   85Gi  7.7Gi    92% 22352334 2028959   92%   /

4.0K	 image.txt
 47G	Applications
436K	Creative Cloud Files
4.0K	DeployStudio_log.txt
9.5G	Library
1.0K	Network
4.8G	System
4.0K	User Information
4.0K	Users
2.3G	Users_old
 52K	Volumes
2.3M	bin
4.5K	dev
4.0K	etc
1.0K	home
4.0K	installer.failurerequests
1.0K	net
1.3M	opt
4.5G	private
1.1M	sbin
4.0K	setup.xml
  0B	t
  0B	tm
4.0K	tmp
608M	usr
4.0K	var


The question is... WHY? Where did 10 gig of disk space go?

Removing folders with less than 100MB makes it easier to compare

Code:
17GB available:
 47G	Applications
9.4G	Library
5.1G	System
2.3G	Users_old
4.5G	private
608M	usr

8GB available:
 47G	Applications
9.5G	Library
4.8G	System
2.3G	Users_old
4.5G	private
608M	usr


There is a VERY small increase in used space, a few hundred MB, but it's showing a total difference of 10GB.

My only current theory on this is there's a folder somewhere that has a lot of small files in it, and it's the folder size causing this problem. The last time I ran into this, over 100GB of space was missing, and a safe boot fixed it. (and it was NOT due to fsck, I had already repaired the disk, it was deleting temp files or something somewhere)

Ideas?
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#37166 - 11/13/15 12:15 PM Re: missing gigs of disk space [Re: Virtual1]
artie505 Online


Registered: 08/04/09
Maybe pretty Probably beyond simplistic, but I wonder if an app such as GrandPerspective that displays a graphic representation of used disk space would show you something that Terminal isn't showing you.


Edited by artie505 (11/13/15 12:30 PM)
_________________________
The new Great Equalizer is the SEND button.

In Memory Of Harv: Those who can make you believe absurdities can make you commit atrocities. ~Voltaire

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#37185 - 11/14/15 07:39 AM Re: missing gigs of disk space [Re: Virtual1]
Ira L Online


Registered: 08/13/09
Loc: California
Are the drives (SSD's) for each from the same manufacturer? Different overhead by brand, perhaps?
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On a Mac since 1984.
Currently: 27" iMacs, Macbook Air, macOS 10.14.x,; iPhones, iPods and iPads galore!

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#37214 - 11/16/15 07:30 AM Re: missing gigs of disk space [Re: Ira L]
Virtual1 Offline


Registered: 08/04/09
Loc: Iowa
Originally Posted By: Ira L
Are the drives (SSD's) for each from the same manufacturer? Different overhead by brand, perhaps?

Hardware is identical, two of 21 iMacs in a lab, bought at the same time. I'll be looking deeper into this later today.
_________________________
I work for the Department of Redundancy Department

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#37219 - 11/16/15 09:48 AM Re: missing gigs of disk space [Re: Virtual1]
dkmarsh Offline

Moderator

Registered: 08/04/09

Maybe try comparing contents of the various directories within /var?

I notice your terminal output shows only (presumably) the size of the /var folder, not its contents. OMM, in addition to the swap files in /var/vm, there are hundreds of megabytes of data in /var/db/dyld, /var/folders/x3, and /var/run/diagnosticd, not to mention various files in /var/log.
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#37253 - 11/18/15 05:42 AM Re: missing gigs of disk space [Re: dkmarsh]
Virtual1 Offline


Registered: 08/04/09
Loc: Iowa
Originally Posted By: dkmarsh
I notice your terminal output shows only (presumably) the size of the /var folder, not its contents.

ls would display directory size, df should add up directory contents, recursively. But it doesn't account for cluster size overhead. And I suspect that is where the space is going, in directories full of lots many thousands) of tiny files.
_________________________
I work for the Department of Redundancy Department

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#37281 - 11/18/15 11:56 AM Re: missing gigs of disk space [Re: Virtual1]
dkmarsh Offline

Moderator

Registered: 08/04/09

Originally Posted By: Virtual1
ls would display directory size

I was referring to the output of your du -shx * command:

Originally Posted By: Virtual1
4.0K var

I don't see any instances of ls in your post...
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dkmarsh • member, FineTunedMac Co-op Board of Directors

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#37283 - 11/18/15 12:15 PM Re: missing gigs of disk space [Re: dkmarsh]
Virtual1 Offline


Registered: 08/04/09
Loc: Iowa
oh, if you were specifically focusing on var, var isn't a folder. it's a symbolic link. (basically an alias) So is etc and tmp. those are all in private. oooold unix throwback.
_________________________
I work for the Department of Redundancy Department

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