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Expanding a raw image file | ABOUT | TAGS

January 13, 2011 | TAGS:

On one of my customer’s devices, the backup software requires that the backups go to a separate partition (or drive).  However, the customer only has one raid array and the bulk of the space is in /home.   To work around this limitation, I created a raw image file called backup.img, which gets mounted as /backup.   After the software performs its local backup, I use duplicity to backup /backup remotely to a backup server at my location (with encryption).

Today I got an alert that /backup was running low on space.  It was an 80GB image and 61GB was in use, leaving only 15GB free.  Now, this amount of free space should last quite a while.  However, the software (cPanel)  has a known issue for years that the 80% limit is hardcoded into the program.  I can change this, but every time cPanel updates, it overwrites that change.

So to be proactive, I decided to go ahead and increase the image size.

In order to increase the size of an image, you simply unmount your raw image and use the dd command.

check the filesystem

/sbin/e2fsck -f backup.img

resize the filesystem

/sbin/resize2fs backup.img

check the filesystem again

e2fsck -f backup.img