ownership & permissions: external drive LOST!!!

Question

ownership & permissions: external drive LOST!!!

K, so I have a new Lacie 160 gig external drive for the Mini (the cool one that sits underneath), not even 3 weeks old. I was setting up my FTP server to share with a friend and figured I should change the permission so he (or anyone) wouldn't have access to my most personal files. I did Get Info and under You Can, made sure it said Read & Write, under Owner made sure it said the same, and under Group and Others, selected No Access and then tried to hit Apply to enclosed items... and that's where I started running in to problems.

It said i couldn't apply to all things because I didn't not have permission. I hit Ignore Ownership, thinking that might allow me to proceed but it still didn't work. At some point in this, I lost all access completely. No matter what I did, what I locked and unlocked, it said i did not have access. I could open the drive, and all the files and folders were listed, but when I went to play something/view something/open a sub folder, it said no access. A sub-folder would open, but it would say Zero Items. After talking about the problem with a friend, I decided to unmount it and remount and hopefully that would solve it. I ejected the image, and turned it off, then turned it back on. No mount. I started the system and still no mount.

I ran Disk Utility and verified the volume. It shows up in the System Profiler when I click the firewire thing, and it also showed up in the Disk Utility menu, although the Lacie icon was gone, I just had a generic file icon (piece of paper with a folded corner) in it's place.

Now, I started digging around in the Mac Help and found this little bit of worthwhile information that would have been extremely helpful before I did all this. It says, under Ownership & Permission:

To ignore the ownership of the files on a drive:
Select the disk and choose File > Get Info.
Click the triangle next to Ownership & Permissions.
Select the "Ignore ownership on this volume" checkbox.

Not all files are accessible when this option is selected. Files with permissions that don't allow their owners to read from or write to them remain inaccessible.

You should not select this option for a disk you plan to use to back up files, because user and group information might be lost.

So okay, that's all well and good, but if this does happen, how do I get it back??

I'm really freaking out because if I can't get it back I've lost all my personal files for the last 4 or 5 years. This was supposed to be my back-up. I haven't bought a second or third drive yet for the double or triple redundency. This is my first time with an external drive more complex then the old 100 meg zip drives.

Help, if you know a way!

Thanks,
Stephen

Mac Mini Mac OS X (10.4.5)

Mac Mini Mac OS X (10.4.5)

Posted on Apr 3, 2006 9:44 AM

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Answer 1

Apr 3, 2006 10:47 AM in response to korealignments

Hi Stephen,

Open the Terminal application, issue this command and post the results:

ls -ol /Volumes

Now I need to know who you are on your computer, issue this command and post the results:

id

You can copy and paste the results.

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Answer 2

Apr 3, 2006 12:50 PM in response to Mark Jalbert

ls -ol /Volumes
total 8
lrwxr-xr-x 1 root admin - 1 Apr 4 03:57 Macintosh HD -> /
d---r-xr-x 15 stephenl stephenl - 544 Apr 3 03:47 Slave
Stephen-Leavys-Computer:~ stephenleavy$

id
uid=501(stephenleavy) gid=501(stephenleavy) groups=501(stephenleavy), 81(appserveradm), 79(appserverusr), 80(admin)
Stephen-Leavys-Computer:~ stephenleavy$

Hope this helps.
Thanks,
–S–

Mac Mini Mac OS X (10.4.5)

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Answer 3

Apr 3, 2006 1:21 PM in response to korealignments

Your hard drive Slave cannot be read, write, or executable (rwx) by the owner. This is probably why the drive doesn't seem to mount. First you need to make sure permission are active on the drive. Use this command to set the drive to be permissions aware:

vsdbutil -a /Volumes/Slave

Now check to see if the drive is permissions aware with this command:

vsdbutil -c /Volumes/Slave

The text output from this command should be:

Permissions on '/Volumes/Slave' are enabled.

Post back with a confirmation that the drive has permissions enabled and I'll post a command to fix the permissions.

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Answer 4

Apr 3, 2006 9:09 PM in response to Mark Jalbert

k, this is what I got:

stephenleavy$ vsdbutil -a /Volumes/Slave
###
### You must be root to perform this operation.
###
Stephen-Leavys-Computer:~ stephenleavy$ vsdbutil -c /Volumes/Slave
No entry found for '/Volumes/Slave'.
Stephen-Leavys-Computer:~ stephenleavy$

I do have multiple users enabled on this computer, but I am the admin, I don't know if that has anything to do with the 'root' comment.

–S–

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Answer 5

Niel

Level 10

742,097 points

Apr 3, 2006 9:53 PM in response to korealignments

Choose Go to Folder from the Finder's Go menu and enter /Volumes/ as the folder's location. Next, open the Terminal in the /Applications/Utilities/ folder while keeping the Volumes folder open. Type the following into the window:

chmod 775

followed by a space. Drag the volume in question into the Terminal window and press Enter. If the disk has Mac OS X installed, replace the 775 with 1775, or use the Repair Permissions command in the Disk Utility to fix the disk. Log out and back in, and see if the drive reappears on your desktop; if not, use:

sudo chown shortname

and then drag the volume back into the Terminal window, replace shortname with the short name of your current user account, type in your administrator password, and press Enter. Log out and back in. An external drive must allow all accounts to be able to read it before any account(with the possible exception of root) can access it at all; to deny people access to items on the drive, change the permissions on individual folders instead.

(11491)

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Answer 6

Apr 4, 2006 3:45 AM in response to korealignments

Stephen,

I'm sorry for the confusion. Normally, I run any command that maniputlates the OS from a root shell. Only the root user can enable or disable permissions on a volume in the CLI. Let me further explain what is going on. The drive Slave is attaching to the root file system (boot drive). This is good. It doesn't mount because you cannot rwx in the drive. Fixable. The data on the drive is intact. The drive was set to ignore permissions. Fixable, you didn't want to do this in the first place. Niel has good instructions on how to change the rwx part of permissions so that the drive should mount (chmod 775 /Volumes/Slave). But you can't change the owner or group of a file on a volume that is set to ignore permissions even as root. Tiger's "improvements" further mask whether a volume or a file on a volume are set to the magic "unknown" user (ignore permissions). At this point, please post if you tried Niel's suggestions and what the results are.

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Answer 7

Apr 4, 2006 4:48 AM in response to Niel

Niel, it worked, my thanks to both of you. I really appreciate it.

–S–

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Answer 8

Apr 4, 2006 6:18 AM in response to korealignments

You should check the drive Slave and make sure it is not set to ignore permissions. You can check in the Get Info window or use the command I gave you in the previous post-

vsdbutil -c /Volumes/Slave

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Answer 9

ffelix

Level 1

0 points

Jun 12, 2006 11:06 PM in response to Mark Jalbert

I see that this thread is a few weeks old now, but hopefully there's still someone out there.

I have the same problem, but I'm unable to resolve it with the information in the thread--it seems like maybe something changed?

The command:

vsdbutil a- /Volume/Slave

returns this:

vsdbutil: Couldn't get volume information for '/Volume/Slave': No such file or directory
vsdbutil: no valid volume UUID found on '/Volume/Slave': No such file or directory

I also looked at Niel's drag & drop solution, but the drive does not appear in the directory, so there's nothing to drag (it does appear under 'disk utility').

Thanks for any help you can provide!

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Answer 10

ffelix

Level 1

0 points

Jun 12, 2006 11:20 PM in response to ffelix

Oops. I actually did run the test using my drive's name ('Media'), rather than 'Slave', but the results were the same. Also this:

ls -ol /Volumes
Password:
total 8
lrwxr-xr-x 1 root admin - 1 Jun 12 17:50 MacHD -> /
d---r-xr-x 15 unknown unknown - 612 Mar 4 17:46 Media

Thanks again.

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Answer 11

ffelix

Level 1

0 points

Jun 12, 2006 11:40 PM in response to ffelix

What a freakin' gumby--after all these years you'd think I'd triple check the syntax before spending all day fiddling around then posting twice (wait, I just did it again).

Problem solved. You guys are absolutely awesome. Sorry to waste your time.

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Answer 12

Jun 15, 2006 1:36 PM in response to korealignments

Thanks Mark & Niel...we had a similar problem today, and were able, even through your 'offline' help, to get access to our previously lost disk.
Thanks again,
Raf R

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Answer 13

No_RTFM

Level 1

0 points

Jun 19, 2006 11:43 PM in response to Niel

Thanks Neil!

The 'chmod 1775' instructions worked flawlessly. (I'm not a highly religious man, but right now, you are right up there on my omnipotent list!)

Awesome regards,

Jeff

Powerbook 15" Titanium, G4 Cubes Mac OS X (10.4.6)

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