How to change owner of mount point

Question

We have moved mysql data directory to another disk, so now /var/lib/mysql is just a mount point to another partition. We set the owner of the /var/lib/mysql directory to mysql.mysql.

But everytime we mount the partition, the ownership changes to root.root. Because of this, we couldn't create additional MySQL database.

Our fstab entry:

/dev/mapper/db-db   /var/lib/mysql    ext3    relatime        0       2

How to change the owner of mount point to user other than root?

Cristian Ciupitu · Accepted Answer · 2011-05-17T20:09:44.863

You need to change the permissions of the mounted filesystem, not of the mount point when the filesystem is not mounted. So mount /var/lib/mysql then chown mysql.mysql /var/lib/mysql. This will change the permissions of the root of the MySQL DB filesystem.

The basic idea is that the filesystem holding the DB needs to be changed, not the mount point, unless its path has some issues, e.g. lib can only be read by root.

score 50 · Answer 2 · answered Sep 29 '10 at 16:05

50

also

mount device mount-point -o uid=foo -o gid=foo

if group need to be changed too

answered Sep 29 '10 at 16:05

2

Where the uid foo is the name of the user you want to be the owner of the mount point. And gid foo is the name of the user group, generally the same as the user name. In doubt just type ls -l in your home directory and check the first and second names respectively. – Zequez Sep 12 '12 at 17:35
3

This only works on filesystems that don't store UNIX ownership, like vfat and ntfs. – enigmaticPhysicist Jul 23 '21 at 00:00

Frank N · Answer 3 · 2021-07-23T17:38:10.697

16

Important disclaimer (learned that from comments):

uid and gid flags only work on filesystems that don't support Linux permissions schema - ie, FAT and NTFS, among others

Thus this is NOT a correct answer to OP but helpful to others

Add uid and gid like these:

/dev/mapper/db-db  /var/lib/mysql ext3  relatime,rw,exec,uid=frank,gid=www-group        0       2

You can use actual user/groupnames (beware of spaces) or numeric uid, gid values. I added rw and exec which might further help you prevent access troubles (presuming you are on a development system, not a production server).

PS: For even more access (if desired), add ",dir_mode=0777,file_mode=0777"

edited Jul 23 '21 at 17:38

answered Apr 24 '12 at 12:18

Frank N

640

3

No, it's relatime. http://lwn.net/Articles/244829/ – endolith Aug 13 '12 at 16:45
17

-1 because uid and gid flags only work on filesystems that don't support Linux permissions schema - ie, FAT and NTFS, among others. See http://askubuntu.com/a/34068/329506 – mgarciaisaia Dec 11 '15 at 20:38
2

yeah,i ran into the uid/gid issue - is there a solution? – tofutim Sep 26 '16 at 15:49
1

This helped me with my FAT32 drive. Thank you. – Naeem Khan Jul 18 '19 at 18:52

Tom Werner · Answer 4 · 2009-07-11T12:34:37.640

8

Make sure you change the permissions when the filesystem is not mounted - doing it while mounted has never worked for me.

Additionly, you can add the 'user' option to your fstab, example:

/dev/mapper/db-db   /var/lib/mysql    ext3    relatime,user        0       2

This should also mean that the mount command (if it needs to be called) won't need root privileges to mount that volume. Not changing your fstab will not stop you fixing your issue though!

edited Jul 11 '09 at 12:34

answered Jul 11 '09 at 12:25

Tom Werner

305

this is right answer – QkiZ Oct 13 '23 at 22:48

score 2 · Answer 5 · answered Jul 11 '09 at 13:14

2

I usually do this on empty unmounted directory

chmod 777 <directory>

Then do

chown -R mysql.mysql <directory>

Then in /etc/fstab do

<device>    <directory>  ext3   user,defaults 0 2

Then use

mount -a

to mount all filesystems listed in /etc/fstab.

This works for me. Give it a try

answered Jul 11 '09 at 13:14

Saurabh Barjatiya

4,723

Hi @saudabh. You just saved me a few working hours on this very good answer. – Mikko Ohtamaa Feb 15 '22 at 09:34

score 1 · Answer 6 · edited Oct 16 '17 at 14:28

1

If you want to only do it as part of the mount command line, you can use the -o switch and do:

mount device mount-point -o uid=foo

That will change the owner of the mount point to user foo instead of root.

edited Oct 16 '17 at 14:28

phuclv

179

answered Jul 11 '09 at 17:10

Nasko

727

score 0 · Answer 7 · answered Jun 08 '21 at 17:30

Recently I had fallen into a similar problem. And this is what I did:

In the /etc/fstab:

UUID=xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxx /mnt/minimal_dev_env ext4 errors=remount-ro 0 2

In My Ubuntu Clipboard Extension:

Added this following COMBINED command:

sudo mount -a && sudo chown -R mysql:mysql /mnt/minimal_dev_env/mysql && sudo systemctl restart mysql && ls -la /mnt/minimal_dev_env/mysql

for mounting. And,

sudo systemctl stop mysql && sudo umount /mnt/minimal_dev_env/ && ls -la /mnt/minimal_dev_env/

for unmounting.

score 0 · Answer 8 · answered May 18 '23 at 15:29

0

Would it work to set fstab entry like this?

/dev/mapper/db-db   /var/lib/mysql    ext3    relatime,mode=0755,uid=1000        0       2

where uid is ID of a user returned by "id" command.

answered May 18 '23 at 15:29

16851556

506

score 0 · Answer 9 · answered Mar 20 '24 at 23:05

You can also use setfacl to set permissions on a mount point.

I hit this issue with a manually created (via udev rules) zram device.

To set 755 permissions with myself as owner:

sudo setfacl -m "u:stuart:rwx" /var/build/sources
sudo setfacl -m "g:stuart:rx" /var/build/sources
sudo setfacl -m "other:rx" /var/build/sources

source: Arch Linux Wiki

How to change owner of mount point

9 Answers9

Important disclaimer (learned that from comments):

Linked