What have you done with my Volumes?
July 15, 2010 3:27 PM   Subscribe

MacFilter: Extraneous OS X volume suffixes?

I'm running OS X 10.6.3 on a 2009 unibody Macbook. I use Carbon Copy Cloner to create and maintain a bootable clone of my internal HD on an external USB 2.0 HD (both HDs are the same size, with one partition). I don't usually keep the external drive attached; instead, I have CCC set to prompt me to do a backup when it recognizes that I've attached the appropriate volume (which I believe it does via GUID). Let's say the volume name on the backup drive is "Backup".

Over time, I've noticed that my /Volumes directory contains "ghosts" of Backup. So for example, even when the external drive is physically disconnected, I'll see:

/Volumes/Backup 2
/Volumes/Backup 3

These don't show up on the desktop. When I actually connect the external drive, I'll see:

/Volumes/Backup 4

and "Backup" will appear on the desktop.

The only information I can find regarding this behavior is:

Dealing with Mac OS X Volume Suffixes

which explains how to "fix" the problem, but not much on how it actually occurs or what is really going on. In addition to be confusing, I notice that the "ghosts" in my case are insidious in that they actually occupy space on my startup disk. My theory is that this is due to CCC getting confused by their presence and at some point essentially backing up the drive onto itself (!).

I'm looking for additional information on how these "ghost" volumes are created, how to avoid them, how they impact applications (esp backup), your experiences with them, etc.
posted by kanuck to Computers & Internet (4 answers total) 1 user marked this as a favorite
When you disconnect your drive, do you click on it and eject it (drag to trash, Command+E, File -> Eject) or do you just yank the cable?
posted by sbutler at 3:59 PM on July 15, 2010

I'm going to go where sbutler is going.

Essentially the OS creates an alias in the Volumes folder for every volume mounted. When you dismount the volume this gets removed.

If you just pop it out this alias gets left behind.

In 10.4 and 10.3 this could create problems with some flash media, as if the alias of the same name was already in the Volumes directory it wouldn't allow the card to mount until you deleted the ghost volume.

If you are properly dismounting I'm going to go with a strange CCC behavior. Like maybe it's trying to dismount the volume to back up and can't? No real idea there, but I've never seen these leftover ghosts from mounted media any other way.

Also, I am sure they are not called aliases, but don't recall what they arre called.
posted by cjorgensen at 5:04 PM on July 15, 2010

"Mount points," they're called. If the drive is unmounted, a simple rmdir Backup\ 2 will remove the directory. OS X will automatically recreate it if needed. This may have side effects but I can't think of any.
posted by Electrius at 7:41 PM on July 15, 2010 [1 favorite]

"Mount points" leads me to "Duplicate mount point in /Volumes after unexpected restart" and some discussion threads regarding scenarios where duplicates arose.

I'm pretty good about dismounting/software "ejecting" external media before physically disconnecting, and in this particular drive's case, I only use it for backups, so it seems even less likely I might forget (unlike, say, a camera memory card).. I may follow up on the CCC forums, as it seems like there was a definitely some weirdness where it chose to start backing up into one of the false mount points (as though it couldn't figure out which one was the real drive).

Thanks all!
posted by kanuck at 10:51 AM on July 16, 2010

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