Remount root filesystem read-only

zsolt_tuser · 04-21-2007, 03:08 PM

Hello,

How can I remount the root filesystem read-only? I want to do that because i want to make a filesystem check with fsck.

Thanks!

osor · 04-21-2007, 03:16 PM

see man mount…
Ex:

Code:

# mount -r -o remount /

zsolt_tuser · 04-21-2007, 03:36 PM

I tried that already, but it doesn't work:

Code:

# mount -r -o remount /
mount: / is busy

osor · 04-21-2007, 04:07 PM

Did you also try

Code:

# umount -r /

zsolt_tuser · 04-21-2007, 04:11 PM

Yes, I tried this also:

Code:

umount -r /
umount: /: device is busy
umount: /: device is busy

osor · 04-21-2007, 04:15 PM

Are you in the middle of a copy or download?

zsolt_tuser · 04-21-2007, 04:23 PM

No, I am not. But however there are for sure files in use because it's the root file system. That's the problem. And i don't know how to force to remount read-only.

zsolt_tuser · 04-21-2007, 07:14 PM

Or is there another method to check the root filesystem without reboot?

osor · 04-21-2007, 07:45 PM

Quote:

Originally Posted by zsolt_tuser

No, I am not. But however there are for sure files in use because it's the root file system. That's the problem. And i don't know how to force to remount read-only.

Personally, I have /var on a separate partition. Perhaps you might stop certain daemons temporarily (syslogd comes to mind).

syg00 · 04-21-2007, 08:47 PM

Try it in single user - init 1 usually, but who knows with Debian.
I'd just force it on the next re-boot.

schlabs · 03-10-2010, 10:15 AM

Hi, i put this only for the record:
I have the same trouble,i cant remount with the "disk busy" letter, but i need to run fsck.reiserfs.
So googling i found this:

Code:

/bin/mount -no remount,ro /dev/sda2

Quote:

Originally Posted by man page of mount

-n Mount without writing in /etc/mtab. This is necessary for
example when /etc is on a read-only file system.

I find this too in http://old.nabble.com/init-1,-root-d...d16786781.html

Code:

man shutdown:

-F     Force fsck on reboot.

or

Code:

touch /forcefsck

mlcurry · 04-27-2011, 04:01 PM

You need to make sure that you gracefully shut down any services that are holding open files before remounting. To do so, run:

Code:

fuser -v -m /

You'll find things like portmap, rsyslogd, atd, etc., containing either "f" or "F" in the flags. All of these should be stopped. Many can be stopped with "service some_service_name stop", with a list of service names found in a location like /etc/init.d. A few processes (like rpc.statd, if it's running) will simply need to be killed. Once this is complete, you can use the above commands to remount your file system.