I have the problem that my machine turned the root filesystem into readonly mode and remounting it as writeable won't work:
# mount -o remount,rw /dev/sda1 /
mount: block device /dev/sda1 is write-protected, mounting read-only
I want to copy some data away from that system and I attached a USB drive and tried to mount it:
# mount -t ext3 /dev/sdb1 /mnt
mount: /dev/sdb1 already mounted or /mnt busy
/mnt is an empty directory, so mounting there should usually work, but it seems that having this directory on a readonly filesystem doesn't make it possible to mount something there.
I think there is no activity going on for /mnt, since the following command doesn't return any output:
# lsof | grep "/mnt" | grep -v grep
There is no other partition mounted as the readonly root filesystem at the moment. Is it possible to still get the attached disk into the directory hierarchy somehow?
Best Answer
The first error message is telling me that you'll need to reboot - there's something wrong with the disk device itself that the kernel can't resolve without a reboot. If you're booted from SAN, look carefully at your boot LUN and make sure there's nothing wonky with it, or the zoning for the SAN, or the export of the LUN.