Error message : device or resource busy

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You may have encountered the error message:

Cannot open /dev/hda9 : device or resource busy

in linux many times..where /dev/hda9 is one of your partitions of your hard drive /dev/hda..and 9 is the partition number.

This can happen due to one of the following reasons:-

1.The device could be mounted somewhere.To fix this

Check /etc/fstab file.

#cat /etc/fstab

We can see that the last line contains /dev/hda9 mounted on /quota folder.

Comment out this line

Open /etc/fstab file with your favourite editor..we will use vi editor here.

#vi /etc/fstab

Go in insert mode by pressing ‘i’ and comment out the line.

Move out of the editor with [esc] and then :wq

Then,

#umount /dev/hda9

#mount –a

Now check with,

#mount

You will not see /dev/hda9 mounted.

2.Another reason may be that the device you are trying to access (or use) is supposedly busy (in use) or that a resource it needs (such as an IRQ) is supposedly being used by another device and can’t be shared. This message is easy to understand if it only means that the device is busy (in use). But it sometimes means that a needed resource is already in use (busy). What makes it even more confusing is that in some cases neither the device nor the resources that it needs are actually “busy”.