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I am, at present fairly new to Linux. I am using an external Sata hard drive to do data analysis on a Linux system. I have mounted and unmounted the ...
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  1. #1
    Just Joined! Mothra's Avatar
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    Apr 2012
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    Unhappy Remounting after 'lazy' unmount help


    I am, at present fairly new to Linux.

    I am using an external Sata hard drive to do data analysis on a Linux system. I have mounted and unmounted the drive several times using the commands
    Code:
    sudo mount /dev/sdc1 /mnt/mf
    and
    Code:
    sudo umount /mnt/mf
    However, after running some programs (and ctl+C sometimes) I was unable to unmount the drive. After looking around on forums, I attempted the command

    Code:
    sudo umount -l /mnt/mf
    Which successfully removed the drive (I could tell by the fact the drive was absent when I typed the command 'df'

    I then powered down the drive and removed it from the computer. I just attempted to re-mount the drive using the usual means described above. However, the prompt says that 'special device /dev/sdc1 does not exist'.

    typing dir in the directory /dev reveals that sdc1 is indeed, not present.

    Does the drive have a new name? if so how do I tell? Is there a quick fix for this? I'm assuming it is because of the 'lazy' unmounting that I did at the last unmount.

    Thanks

  2. #2
    Linux Guru Lazydog's Avatar
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    I had this problem a while back by not unmounting my thumb-drive properly. After a reboot it was fixed and I could use the old drive again. Normally it is the next free drive, in your case sdd1 if it is free.

    I would suggest in the future you look at what is holding the drive up before resorting to the lazy unmount.
    You can find out what is locking the drive with fuser as so;

    fuser -m /dev/sdc1

    This should show you what PID has the drive locked then all you need to do is;

    ps auxw|grep <PID>

    Which should show you the program that has it locked. Then all you need to do is stop the program and the drive should become free to unmount.

    Regards
    Robert

    Linux
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    Linux User #296285
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  3. #3
    Just Joined! Mothra's Avatar
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    Thank you,

    I would just like to point out to others that the key was the change to sdd1....

    Lazydog , I did run the fuser -m /dev/sdc1 command before I did the lazy unmount... it returned a process that I couldn't identify. it was something along the lines of 2763c. Runnign the ps auxw|grep 2763c command only told me the 2763c was in use (kill didn't work either). Therefore, since I was able to get the lazy unmount to remove the drive from df, I moved on.

    Thanks again.

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