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Arie K
Asked: 2009-07-12 04:07:20 +0800 CST

How to change owner of mount point

  • 772

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?

mount unix permissions fstab

7 Answers

  1. Best Answer

    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.

    • 55

  2. also

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

    if group need to be changed too

    • 47

  3. 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"

    • 13

  4. 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!

    • 6

  5. 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

    • 2

  6. 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.

    • 1

  7. 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.

    • 0