I moved my EFI partition which caused me to enter emergency mode on reboot.
mount -a confirmed fstab had the the UUID of the old partition...it wasn't mounting and that caused emergency mode.
You can't do ANY of the standard remount,rw tricks that normally work... it will always give you an error message the mount doesn't work
Sure, I could start from the USB stick and edit /etc/fstab, but isn't there an easier way?
This question has been around for 10 years and most people answer with a remount as rw, but that always fails.
The clever way is simply mount the / partition on /mnt like:
mount /dev/sda1 /mnt
This mounts it read-write and you just edit /mnt/etc/fstab to change the new UUID for your partition which you can get from either blkid or ls -lha /dev/disk/by-uuid
However, the readonly filesystem will NOT see your changes, so you think you've failed. You'll look at /etc/fstab and it will appear unchanged (at least under btrfs it looks unchanged).
However, when you reboot, you are back in business.
I re-sized my EFI partition down to 260MB, but had to remove it to do that which causes the UUID to change. Just changing the /etc/fstab with the new UUID is all that you need to do so you don't run into trouble. Best to do that when you move the partition, rather than after the fact.
I have RHEL 7.9 installed and here is what I did to edit the fstab after copying from one machine to another using scp.
mount -o remount,rw /dev/sda2 #sda2 is where my root directory is located.
I was then able to open in vim and save the UUID changes I had to make. Worked like a charm.
Related
I accidently formatted my ntfs windows partition with "mkfs.ext4".
I was able to recover it with testdisk but it seems that the windows partition was hibernated,
so whenever i tried to open windows it starts repairing disk errors which was taking too long,
so i manually chkdsk ,to which after some time it started telling -"unreadable sector........
which also took very long so i shut it down.
In kali linux whenever i tried to mount it with "mount /dev/sda3 /mnt -t ntfs -r"
it mounts but many of the folders are empty including windows,program files,Users.
I am new to linux,can you tell me steps to recover my files if possible windows...
Thanks in Advance.
Use sudo ntfsfix /dev/sdXY where XY is the partition name. ex:sda4. use gparted to find partition name. Then mount. It may help.
First check to see it the partition is mounted, it maybe mounted as Read-only. Then issue the mount command with the options.
sudo mount -t ntfs-3g -o remove_hiberfile /dev/yourWindowsPartition /media/yourUser/WindowsPartitionName
Environment is in virtual box,ubuntu 12.04. It has 2 disks, /dev/sda1 and /dev/sdb1 are both ext4 type filesystem.
Since /dev/sdb1 is add after system installed, so I want to mount it manually. I'd try this command:
sudo mount -o user,defaults /dev/sdb1 ~/project
No errors report. Then I get mount info by mount:
/dev/sdb1 on /home/igsrd/project rw,noexec,nosuid,nodev
But when I ls -l to see /home/igsrd I found its permission is still belongs root, so I can't touch anything in it. Why it still belongs root?
I have another machine running ubuntu 12.04,too. I mount another partition with same option will be fine, correct permission(ownership). Are any differences between them?
*nix permissions on a filesystem that supports them natively, e.g. ext4, will be maintained regardless of how it is mounted when using a proper filesystem driver, e.g. the native ext4 driver built into Linux.
Why don't you just (while still root) do this:
chown -R <your-user-name> ~<your-user-name>/project
?
ie the partition of interest is already mounted as read-only.the partition need to be mounted as a rw enabled partition for executing particular lines of script alone.After that the partition should go to it's previous state of read only.
Question is for QNX operating system. And correct way to remount partition as read/write can be done using below command.
mount -uw /
To remout a partition read-write:
mount /mnt/mountpoint -oremount,rw
and to remout read-only
mount /mnt/mountpoint -oremount,ro
you may be interested in remount option.
for example, this command is widely used in rooted androids.
mount -o remount,rw /system
mount -o remount,ro /system
mount(8) - Linux man page
Filesystem Independent Mount Options
remount
Attempt to remount an already-mounted filesystem. This is commonly used to change the mount flags for a filesystem, especially to make a readonly filesystem writeable. It does not change device or mount point.
The remount functionality follows the standard way how the mount command works with options from fstab. It means the mount command doesn't read fstab (or mtab) only when a device and dir are fully specified.
mount -o remount,rw /dev/foo /dir
After this call all old mount options are replaced and arbitrary stuff from fstab is ignored, except the loop= option which is internally generated and maintained by the mount command.
mount -o remount,rw /dir
After this call mount reads fstab (or mtab) and merges these options with options from command line ( -o ).
How can I access and modify /etc/fstab during reboot (maybe accessing to recovery mode) ?
Why this question :
I have updated the virtualbox guests additions in backtrack 5 (as a Virtualbox VM).
I have modified temporary the fstab file to do that but forgotten to turn it back to initial state, like :
mount /dev/cdrom /cdrom
echo "/dev/cdrom /cdrom0 udf,iso9660 defaults,exec 0 0" >> /etc/fstab
So after the guest additions installed, reboot is blocked on mounting this unexisting point.
Thx
edit: maybe to move to serverfault ?
I see two possible solutions to your problem:
Use the recovery mode (if you don't see that in the grub list, edit the default entry and add the word "single" without quotes to the end of the kernel line)
Mount a random .iso file temporarily
Then remove the offending fstab line.
Another option is to boot a Live OS and mount the root filesystem from there. Then you will be able to edit the fstab file.
Once you have the live OS booted
fdisk -l
-find your root partition (usually in the format sda1, sdc1, sda2, etc)
mkdir /mnt/rootfs
mount /dev/sda2 /mnt/rootfs <--sda2 = root partition found in fdisk
cd /mnt/rootfs/etc
-Fstab file should be in there.
I had a typo in my fstab and it boots to a commandline but is readonly, I know what the error is but i can't change it because it's mounted as readonly. I want to mount the filesystem and make the changes. I know I can boot a live distro and edit it that way, but i was wondering if there was an easier way to do it.
It's debian lenny by the way.
Yes, if you end up in single-user mode with a readonly root, try:
mount / -o remount,rw
Maybe a -n is necessary, maybe not. That should remount the root fs read/write (assuming there's nothing wrong with it).
I know that question is outdated, but saw it, because nowadays got in the same trouble.
I broke my fstab manually (make a typo in parameter).
That was very easy to correct fstab from readonly mode. We must mount / in read-write mode.
If /etc/fstab is correct, you can simply type:
mount -n -o remount /
But if /etc/fstab is wrong (as it was in my case), you must give the device name and possibly the type, too: e.g.
mount -n -o remount -t extX /dev/hdaX /
Where extX is your filesystem type and /dev/hdaX -- is partition you use for your root mount point.
To see all your available partitions just type ls /dev/[sh]d*.
#mount -n -o remount,rw /
if /dev/sda1 is the real device, then do:
#mount -n -o remount,rw /dev/sda1 /
#troyane saved my hassle by providing
mount -n -o remount -t extX /dev/hdaX /
I was on Orangepi3 EMMC when I had a typo in UUID of root having ext4 filesystem.
The command remounted in read-write mode and I fixed my fstab
mount -n -o remount -t ext4 /dev/mmcblk2p1 /
My kernel command line looks like this:
$ cat /proc/cmdline
root=/dev/sda4 ro
$
Tell grub that it should omit passing "ro" to the kernel when booting (pressing esc, e on the entry you want edit will allow you to edit the arguments given to the kernel), and it will mount your root file system not read only anymore. Then you can change your /etc/fstab and restart.
In my case, in grub2 after pressing "e" I have changed "ro" to "rw init=/bin/bash" then the root filesystem is mounted read and write so I could change the content of /etc/fstab file.
If you have something wrong with your /etc/fstab file. Please follow the following steps.
boot your ubuntu system or restart your computer
since you can not start your system, you will encounter some errors like
“a start job is running for dev-disk-by....
(you may need pressing F2 key to come the linux command terminal to see this)
use command vi /etc/fstab and edit your fstab file
use # to commend out some problems and add something you want put in the fstab file.
finish editing. hit shift+z and save the modification
use command reboot to restart your system
it works again
Please comment here, if you have questions