Just got rMBP - why is so much disk space used by clean install of OS X?

[gwelmarten]

Hi Guys
So, I just took delivery of my Retina MacBook Pro. Just started playing with it and concerned that already 35GB of HDD space has disappeared!

So, I looked in Macintosh HD and got this:
Applications: 6.5GB
Library: 3.9GB
System: 5.4GB
User Information: 49b
Users: 2.1GB

Which adds up to roughly 18GB.

When I enable hidden folders / files, I get a folder called 'Private' appear. This is sized at 18.1 GB. Does anybody know what this is? Isn't all the OS X stuff in the System folder?

Is Private just another place where I can find my other files? Like they are a special Alias as it's Unix? Why would a default install of OS X take up so much space?

Sam

UPDATE: See attachment for breakdown of usage.

 

[switon]

RE: That /private directory...

(teken down)

 

[ToddSoc]

Safe sleep eats up a ton of disk space, the amount of your memory plus a little bit extra.

 

[gwelmarten]

Hi gwelmarten,

Actually, I don't believe 18GB for a fresh install is too far off the mark. Many modern OSes use this much or more space.

About that Private folder you refer to: you will note that several system directories, like /etc, /var, and /tmp are symbolically linked (aliased) to /private/etc, /private/var, and /private/tmp. To see everything in these directories will require administrator privileges (sudo). So be careful when looking at disk sizes that you don't miss things because of privilege problems or count some things twice because they are linked to another directory. My /private/var also has 18GB in it (/private holds databases, log files, mail, the root login directory, temporary files, but most importantly it has the swapfile0 and sleepimage files that take up the vast bulk of the space in /private/var).

I don't believe you have anything to worry about. Once you started using your rMBP the swapfile0 started filling with page swaps and once your rMBP went to sleep the sleepimage file was created to swap out your RAM to the SSD. This is entirely normal behavior. And the sizes of these files will stay more-or-less what they are today.

Hope this helps...

Regards,
Switon

Update: So, as you see in your FindSpace pane, the /var holds 18GB and /private is just repeating this 18GB, I believe. If you actually look in /private/var/vm you should see the two large files, swapfile0 and sleepimage. If these two files don't take up most of the space in /private (and your machine is new so little database and log files), then you might look into where the actual space is being utilized.

A suggestion: You might perform a "sudo df -h" in a Terminal window to see how much space is taken by each mounted volume. Also do a "sudo du -h /private/var" to see how much space is taken by the various subdirectories of /var.

Hi
Thanks for such a detailed response. I just wanted to check when you replied you read the bit about it taking 35GB - with 18GB being the private folder (and var), as you only referred to 18GB. So, altogether, once the computer has being used, put to sleep once and rebooted with nothing installed or changed since it was first started being used, 35GB of usage is acceptable?

Sam

----------

Safe sleep eats up a ton of disk space, the amount of your memory plus a little bit extra.

Yeah, using 16GB's of RAM so that's going to be partly responsible. Thanks.

 

[switon]

Re: 35 gb...

(removed)

 

[Lord Appleseed]

It could be the mobile backup. Mine was at 30 GB.

 

[switon]

RE: Mobilebackups...

(removed)

 

[gwelmarten]

It could be the mobile backup. Mine was at 30 GB.

Mobile Backup as in the backup folder created by iTunes in Library that contains the backups of iOS devices? This computer is new - I have not plugged in any ioS devices, so I don't think this is the problem. Thanks anyway.

----------

Hi Lord Appleseed,

Mobile backups as well as Document revisions can chew up large amounts of disk space (the mobile backups, by the way, are deleted when disk space gets low), backups more-so revisions less-so.

In gwelmarten's case, however, I don't think this is the problem since the mobile backups are stored in the /.MobileBackups directory and document revisions are stored in /.DocumentsRevisions-V100 and neither of these should show up in his /private/var directory which had 18GB in it. We'll just have to wait to see if gwelmarten performs the "sudo ls -alh /private/var/vm" terminal command and finds roughly 16GB of storage in his swapfile0 and sleep image files. This is still my best guess as to where his 35GB are located: roughly 18GB in the OS and User files, and roughly another 16-18GB in his swapfile0 and sleepimage files. What do you think?

Regards,
Switon

Hi
So, I ran 'sudo ls -alh /private/var/vm'
sleepimage is 16GB
and swap file is 64MB.

Should the swap file be larger?

----------

Hi gwelmarten,

Actually, I don't believe 18GB for a fresh install is too far off the mark. Many modern OSes use this much or more space.

About that Private folder you refer to: you will note that several system directories, like /etc, /var, and /tmp are symbolically linked (aliased) to /private/etc, /private/var, and /private/tmp. To see everything in these directories will require administrator privileges (sudo). So be careful when looking at disk sizes that you don't miss things because of privilege problems or count some things twice because they are linked to another directory. My /private/var also has 18GB in it (/private holds databases, log files, mail, the root login directory, temporary files, but most importantly it has the swapfile0 and sleepimage files that take up the vast bulk of the space in /private/var).

I don't believe you have anything to worry about. Once you started using your rMBP the swapfile0 started filling with page swaps and once your rMBP went to sleep the sleepimage file was created to swap out your RAM to the SSD. This is entirely normal behavior. And the sizes of these files will stay more-or-less what they are today.

Hope this helps...

Regards,
Switon

Update: So, as you see in your FindSpace pane, the /var holds 18GB and /private is just repeating this 18GB, I believe. If you actually look in /private/var/vm you should see the two large files, swapfile0 and sleepimage. If these two files don't take up most of the space in /private (and your machine is new so little database and log files), then you might look into where the actual space is being utilized.

A suggestion: You might perform a "sudo df -h" in a Terminal window to see how much space is taken by each mounted volume. Also do a "sudo du -h /private/var" to see how much space is taken by the various subdirectories of /var.

Hi
Now done this as well: 'sudo du -h /private/var'
Only bits of interest are:

 16G	/private/var/vm
 17G	/private/var

Sam

 

[switon]

RE: Swap file...

(taken down)

 

[Puevlo]

The vast majority of Mac OS X is actually uncompiled code which is why it is so much bigger than you would expect. This allows Apple to push out updates and bug fixes far quicker than would normally be possible with compiled binary.

 

[gwelmarten]

Hi Sam,

So now you know where the extra disk space disappeared to, it is in the sleep image. Since you have 16GB of RAM, this file should be 16GB in size, which it is, in order to write all that RAM to disk when you rMBP goes to sleep. Because you have 16GB of RAM also means that until you use all of that RAM up, you won't page very much out to disk, so the swapfile0 is relatively small. If you are doing some very memory intensive things, say with Aperature, iMovie, of Final Cut Pro that require large amounts of memory, you won't need to swap out many pages to the swapfile0.

The extra 1GB in /private/var that is not in /private/var/vm are things like other databases, mail spool, log files, /root, jabber files, etc. It is reasonable that all of these other files add up to a GB.

In summary, I think your system is healthy and there is no unaccounted for disk utilizations. My advice: just enjoy you new rMBP!

Switon

P.S. On a laptop when performing Time Machine backups to an external disk drive, when the external drive is no longer available, say when you leave home and take your rMBP to the office with you, the Time Machine still makes hourly backups, but they are stored locally (local snapshots) on the SSD of your rMBP until the next time you return home and Time Machine can resume backing up to the external disk drive. The Finder does not list the disk space that these local snapshots use since this space is recovered whenever your disk goes above 80% utilization. You can see how much space is dedicated to local snapshots through the Apple -> About this Mac -> More Info -> Storage pane, the Backups number tells you how much disk space is currently being used by local snapshots.

Thank you so much for your reply. Now I feel much better! I will enjoy it - it's amazing. Just getting used to it to take it to University for a computer science degree.

Thanks,

Sam