CentOS - May 2008 - Setting Group owner of files on USB drive

I just got a 8Gb flash drive and went to copy a bunch of files onto it.  
I wanted to perserve everything, so I just took my archiving rsync 
command and altered it to go to localhost:/media/RALLY2/ (name of flash 
drive).  I am getting errors with changing the group owner.  Huh?

So I try to just use mkdir to create a directory on the flash drive.  
The directory has a group of root ???

So I try a chgrp and get:

[root at mine me]# chgrp me /media/RALLY2/Stuff
chgrp: changing group of `/media/RALLY2/Stuff': Operation not permitted


OK why can't I set the group to something other than root?

ls -lstr /media/
total 4
4 drwxr-xr-x 3 me root 4096 May 30 16:28 RALLY2

and of course for /media:

 8 drwxr-xr-x   3 root root  4096 May 30 16:18 media

On Fri, May 30, 2008 at 04:37:58PM -0400, Robert Moskowitz enlightened
us:
> I just got a 8Gb flash drive and went to copy a bunch of files onto it.  
> I wanted to perserve everything, so I just took my archiving rsync 
> command and altered it to go to localhost:/media/RALLY2/ (name of flash 
> drive).  I am getting errors with changing the group owner.  Huh?
> 
> So I try to just use mkdir to create a directory on the flash drive.  
> The directory has a group of root ???
> 
> So I try a chgrp and get:
> 
> [root at mine me]# chgrp me /media/RALLY2/Stuff
> chgrp: changing group of `/media/RALLY2/Stuff': Operation not permitted
> 
> 
> OK why can't I set the group to something other than root?
> 
> ls -lstr /media/
> total 4
> 4 drwxr-xr-x 3 me root 4096 May 30 16:28 RALLY2
> 
> and of course for /media:
> 
> 8 drwxr-xr-x   3 root root  4096 May 30 16:18 media
> 
Most likely the device is formatted as FAT32, which has no concept of
permissions.

Reformat it, ignore the errors, or modify your rsync command to not preserve
uid/gid.

Matt

-- 
Matt Hyclak
Department of Mathematics 
Department of Social Work
Ohio University
(740) 593-1263

Matt Hyclak wrote:
> On Fri, May 30, 2008 at 04:37:58PM -0400, Robert Moskowitz enlightened us:
>   
>> I just got a 8Gb flash drive and went to copy a bunch of files onto it.
>> I wanted to perserve everything, so I just took my archiving rsync 
>> command and altered it to go to localhost:/media/RALLY2/ (name of flash
>> drive).  I am getting errors with changing the group owner.  Huh?
>>
>> So I try to just use mkdir to create a directory on the flash drive.  
>> The directory has a group of root ???
>>
>> So I try a chgrp and get:
>>
>> [root at mine me]# chgrp me /media/RALLY2/Stuff
>> chgrp: changing group of `/media/RALLY2/Stuff': Operation not
permitted
>>
>>
>> OK why can't I set the group to something other than root?
>>
>> ls -lstr /media/
>> total 4
>> 4 drwxr-xr-x 3 me root 4096 May 30 16:28 RALLY2
>>
>> and of course for /media:
>>
>> 8 drwxr-xr-x   3 root root  4096 May 30 16:18 media
>>
>>     
>
> Most likely the device is formatted as FAT32, which has no concept of
> permissions.
>
> Reformat it, ignore the errors, or modify your rsync command to not
preserve
> uid/gid.
Unfortunately, I have to use it on Win systems as well...

On Fri, May 30, 2008 at 4:37 PM, Robert Moskowitz <rgm at htt-consult.com>
wrote:
> I am getting errors with changing the group owner.  Huh?
>
> So I try to just use mkdir to create a directory on the flash drive.  The
> directory has a group of root ???
>
> OK why can't I set the group to something other than root?
Because it's FAT.

If what you want is all the files on the same group, you may use mount
options to set that.

For example:

mount -o group=mygroup /dev/sdx1 /mnt/myusb

But if you want commands to change groups or permissions, you should
reformat the filesystem. If you need Windows interoperability, you
might want to try NTFS, I don't know if it works, but if you have the
device, the machines and the time for it, you might as well test it.

HTH,
Filipe

I want to thank you all for your comments and the knowledge I gained 
thereby....

Kenneth Burgener wrote:
> On 5/31/2008 3:33 AM, Johnny Hughes wrote:
>> Robert Moskowitz wrote:
>> You can't expect it to maintain ext3 file permissions in a FAT32 
>> partition :D
>
>
> Not necessarily.  If the Linux files do not need to be accessed from 
> the windows environment, you could create an image file, format the 
> image as ext3, mount the image file as a loop device, and treat it as 
> a standard ext3 mount point. 
Since this is only a movable copy of files from my /home/me directory 
structure, I can live with loosing the group and needing to reset it if 
moved back to a ext3 partition.

I will just have to work out the right rsync of cp command to do the 
bulk movement without all those warnings.  SHould only take reading a 
few man pages for that...

Again thanks.