How To FreeBSD Remount Partition

Posted on in Categories , , last updated October 4, 2013

How do I remount partition on FreeBSD operating systes? How do I mount/remount read-only partition in read-write mode without rebooting the systems?

Linux or other Unixish operating systems need to pass the -o remount option to the mount(8) command to remount partition. However, FreeBSD does not require any special option to remount file system. It can use your standard mount command. The mount utility calls the mount(2) system call to prepare and graft a special device or the remote node (rhost:path aka NFS) on to the file system tree at the point node. For example, if your file system is mounted in read only mode then you can remount it using the following command. First, login as root user.

Freebsd remount disk command example

Type the following command as the root user (superuser):
# mount -o rw /dev/ad0s1a /
# mount -o rw /

  • -o : Takes different options as follows:
    1. rw : Read write mount.
    2. ro : Read only mount.

Make sure you replace /dev/ad0s1a and / with appropriate values. See FreeBSD mount command man page for more information.

3 comment

  1. Your first example did not work for me on FreeBSD 6.1, but if I leave the device off (like in your second command), it does work properly as shown here:

    frenzy:~# mount -o rw /dev/ad0s1a /mnt/ad0s1a.ufs/
    mount: /dev/ad0s1a: Operation not permitted
    frenzy:~# mount -o rw /mnt/ad0s1a.ufs/

    Thanks for the tip (I’m a Linux geek, so these subtle differences are annoying)!

  2. If you update an entry in fstab you can test it like this
    mount -o remount /fstabmountpoint

    This will remount ALL mount points mentioned in fstab that are automounted
    mount -o remount -a
    mount -a [-t type] [-O optlist]

    (usually given in a bootscript) causes all file systems mentioned in fstab (of the proper type and/or having or not having the proper options) to be mounted as indicated, except for those whose line contains the noauto keyword. Adding the -F option will make mount fork, so that the filesystems are mounted simultaneously.

    (ii) When mounting a file system mentioned in fstab, it suffices to give only the device, or only the mount point.

  3. That thing doesn’t work. In my case I needed to remount as noexec.
    What works (on my freebsd 6) is:
    mount -u -o noexec /tmp

    Check the manpage for mount.

    Mount -o remount,opts only works on Linux afaik.

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