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Disappearing hard disk space
In some instances, Mac OS X volumes will display a significantly lower remaining disk capacity than expected based on installed applications and residing files. Sometimes the dramatic loss of space can happen suddenly - after a Mac OS X update or application installation - or gradually over time.
One MacFixIt reader recently wrote:
"I updated to Panther last evening. Everything worked fine and there was about 20+ GB of free HD space available. After running Software Update, and updating to 10.3.3 via the Apple Combined Update, I suddenly had only 20 MB of space left."
Aside from limiting expansion of your data set, low disk space (less than 10% of total capacity in most cases) can cause serious performance problems in Mac OS X.
If you suddenly find yourself with less available disk capacity than you expected, there are some fairly easy measures that can reclaim the lost space.
Corrupted B-Tree Mac OS X's HFS+ filesystem makes heavy use of B-Trees, and as such (even though HFS+ has built-in on-the-fly defragmentation) is subject to B-Tree corruption that can result in disk space measurement errors.
In some cases Apple's Disk Utility (located in Applications/Utilities) will be able to resolve these issues and is a good place to start. However, especially when header node problems are involved, third-party tools like DiskWarrior, Norton Disk Doctor, and Drive 10 can sometimes be more effective.
Leftovers from burned media Another thing to keep in mind is that if you burn a CD or DVD, the recording application (the Mac OS X Finder, Toast, iTunes, etc.) will create a temporary file matching the burned media's size.
Generally, if the temporary files are not immediately deleted, restarting will remove them.
Lack of ram and swapfiles If you run low on RAM, Mac OS X's VM system will create swapfiles. Sometimes - even with a healthy amount of installed memory - these files can become extremely large.
Aside from buying more RAM, you can use a tool like Cocktail to delete swapfiles, though they are likely to refill soon after when more applications are launched without a restart.
To keep track of your disk vs. RAM usage, keep a tool like Menu Meters handy. This application can display current memory usage as either a pie chart, thermometer, history graph, or as used/free totals. The Memory Meter menu shows a breakdown of current memory usage and VM statistics. It can also optionally display a paging indicator light when swapfiles are being used.
Re-apply combo updater In some cases, simply repeating the update installation process can restore seemingly lost disk space.
Check for invalid preference files In some cases, .plist (preference) files can inexplicably swell to enormous sizes. The utility Preferential Treatment (which was mentioned in this month's mac.column.ted) an interface for the plutil command, which can find invalid XML files - all valid .plist files are also valid XML.Search for extremely large files In addition to seeking out invalid, possibly swollen .plist files, you can also simply perform a search in the Finder (File -> Find) for files that are suspiciously large; 100 MB, 1 GB or 10 GB depending on your volume size and file mix.
A tool like File Buddy can also help you find such files - visible or invisible.
Log files- such as those generated by the Mac OS X Console - can also swell to 10 GB or larger. You can clear these files by using the above search method, or more easily with a utility like Cocktail, or OnyX (freeware).
Feedback? Late-breakers@macfixit.com.
Resources
shutdown.
especially in the context of Panther.
Swap file size: On my Q16 with only 512 MB RAM, I've discovered the
truth about swap file sizes. The first two are 64 MB each, the third is 128
MB, the fourth is 256 MB, and each of the rest is 512 MB.
So, the first four amount to 512 MB and each that gets created in addition
adds half a GB to the total. I've on occasion had as many as 12 swap files
crowding my system, amounting to 4.5 GB of disk used for VM before the
OS finally starts cleaning up.
I'm confident that doubling my RAM will solve this most of the time,
however I can't afford to upgrade right now and test the difference.
If the ever-increasing size of the swapfiles is bothering you, you can edit
<b>/etc/rc</b> to specify a fixed swapfile size. For example, to make nice
round-number 20 million (decimal) byte files,<P>
Change the line<br>
<b>dynamic_pager -F ${swapdir}/swapfile</b><P>
to<br>
<b>dynamic_pager -S 20000000 -F ${swapdir}/swapfile</b><P>
Just insert "<b>-S 20000000</b>" in the line. <P>
If you have no idea what /etc/rc is, maybe get a geekier friend to do it.
Editing /etc/rc on a Mac! Yay!
Interestingly, my free HD space does not go down significantly over the couple of days it takes for VM to go up from 2 to 8GB.
This VM size is entirely virtual. My VM size is 7.01 GB, but I only have about 2
GB of swapfiles (ls gives 2.5 GB, du gives about 1.8, which suggests that the
filesystem is allocating blocks weirdly).
I can increase my "VM size" by 3.5 GB in about 10s. This is done by allocating
memory without actually using it. OSX is reasonably smart and doesn't make
that memory available until you actually use it.
If you really want to measure the VM size, ls -l /var/vm/. For a
more accurate reading, du -s /var/vm (I don't know why they're different, but
apparently OSX doesn't allocate filesystem blocks until they're used either).
disappeared _after_ running one of the various disk utilities.
Our customers typically have a 20Gig boot partition. A tech will run a
disk utility to check for problems. Some problems are found and "fixed"
but once the utility finishes the 20Gig volume has been "shrunk" to
1.25Gig (one 5Gig volume shrunk to under 200Mb). The volume is toast
at that point. Files physically located beyond the first 1.25Gig all show
zero size. Nothing short of a repartition seems to fix it. If the user's data
was not backed up prior to running the disk utility then it's pretty much
gone.
As far as we can tell there is some pre-existing condition on these
volumes that causes disk utilities to mess up the # of sectors allocated
to the volume. We've seen it occur when using Norton, DiskWarrior and
TechTool. It's occurred at least 6 times that we're aware of over the last
few months.
Has anyone else experienced anything like this?
Are you running Panther 10.3.0? This sounds like the "zero data corruption"
problem know to the initial release of Panther. If you haven't updated to
10.3.1 or higher, you will need to do so to avoid this nasty bug, which I
believe was also related to the use of FileVault. Also be sure that if you are
running any utilities from a boot CD, that they are not running from 10.3.0 as
well.
Diskwarrior cd 3.0.1 uses 10.3, Techtool 4.0.1 cd uses 10.3 but the new
4.0.2 cd uses 10.3.2, Norton Systemworks 3.0 uses 10.3, but 3.0.1 cd uses
10.3.2, Make sure you are using latest cd's using 10.3.2, i don't know if
diskwarrior has made one or not but so far this is what i've seen.
Cocktail and Panther Cache Cleaner, among others, can run the routine Cron
scripts as well as many other useful system maintenance tasks and do so at
your convenience. I recommend regular use of one of these. As for the boot
system of DiskWarrior, TechTool Pro, etc., the best way to deal with this and
related issues is to create a boot partition on a hard drive (internal or
external) dedicated to these utilities. Not only does a hard drive partition
start up much faster than a CD, you can easily keep both the OS and the
utilities updated without worrying about shelling out $20 for a new CD every
time your favorite utility is updated. There is also the convenience of having
access to all your utilities at the same time, eliminating the need to reboot
from separate CDs. If you have to support other machines besides your own,
an external FireWire drive can provide you with a mobile toolkit.
---
Don't anthropomorphize computers.
They hate that.
The cron scripts do nothing particularly important, except log rotation and
cleaning of temp files. I don't think that would shrink a volume from 20 gb to
1.25 GB.
After running Diskwarrior 3.0.1 from the internal of a Powerbook
800 running OS10.3.4 ,trying to do general maintenance on an
external WD 160GB with Oxford 911, the TOTAL DRIVE
CAPACITY was reduced to 128 GB! (which obviously lowered my
available space)
PowerBook G4 running Panther with all updates. There were no recent
changes, I just rebooted and I noticed <i>poof</i> that the space was
gone.
I have just rerun the Combo 10.3.3 updater with no change and
performed a search of my drive with the Find command searching for large
files (visible and invisible).
I discovered that my /private/var/tmp/ directory contains 414 files and
folders that amount to 14+ Gb of space. The dates of the files range from
12/17/2003 to now. This appears to be a major source of my space
problem.
I had been under the impression that the tmp directory was routinely
emptied by the maintenance scripts. Clearly an incorrect impression!
My question is: <b>Can I reboot (to make sure that nothing is actually
using one of the tmp files) and delete the contents of the /private/var/tmp/
directory?</b> Can I do this with the Finder, or do I need to use a special
UNIX command in the terminal? If so, what is the safest command to use?<p>---<br><br />
/////////////////////////////////////<br />
/<br />
/
You shouldn't delete the directory itself, but you can usually delete the files that are in there.
The stuff in there is supposed to be unimportant. If you are running any extra UNIX tools or custom programs, they may be creating stuff. I run my system non-stop and run a lot of programs, from httpd to the dev tools and everything in between, and my /tmp has about 200k of data in there, so it would be interesting to know what's going on with yours.
Many of them appear to be created by StuffIt. Some have names that are the
same as files that only exist in StuffIt archives. They are <i>much</i> larger
than the original files. Some of the files and folders have cryptic names that I
associate with "temp" files.
Shouldn't all of the /tmp/ directories be cleaned out by a maintenance
routine if it is not deleted for some reason by the original program?<p>---<br><br />
/////////////////////////////////////<br />
/<br />
/
As an oversight, the 'periodic' scripts (which run every day/week/month) are
scheduled to run at around 3 AM, so as not to mess up your work schedule.
It is my opinion that all temp files should be deleted by the programs which
created them, though.
frequently crash. G4 MDD 1 Gig, 60 Gig HD actual files should leave about 7
Gig free but it was reduced to about 3.
Ran Diskwarrior, found a few of apples hidden files that were partialy
overwritten, repaired those and now works fine, back to normal.
The routeen scripts run at 3:15AM(daily) every night, 4:20AM every saturday
(weekly) not sure for monthly but probably similar "low time" of computer
use, if computer isn;t on during these times these scripts NEVER run..unless
done so manually..tiny little glitch for those that shut their computers down
at night. Perhaps To be concidered.
omnidisksweeper/">OmniDiskSweeper</a> is an excellent free tool which
can help you find out where your disk space has gone. It will help you quickly
track down which folders and files are occupying the most space.
I was suddenly missing 30 gigabytes and, working my way down the list of
suggestions, I finally tried Omni Disk Sweeper.
Oh! look! a 30 gigabyte MP3 file! I wonder it that didn't show up when I
searched the disk for big files?
Problem solved, thank you very much for the suggestion.
- by LukasM April 19, 2004 4:43 AM PDT
- I have found that Applejack is an extremely useful tool for this kind of
- Like this Reply to this comment
-
Showing 1 of 2 pages (21 Comments)maintenance. Applejack is a shell script that can be run when you boot in
Single User mode (cmd-S at startup) instead of the standard fsck (or other)
routine. It's very easy and it doesn't do any harm if you *read* the
instructions (they always show up if you start Applejack in SU mode so you
can't do any wrong). Like this you can repair the startup disk, clean caches
and the swap files. Under Jaguar you can also repair permissions; this is
broken in Panther due to an Apple bug in diskutil and will be automatically
skipped by Applejack.
http://sourceforge.net/projects/applejack