How to add a new entry to fstab?

Question

I mount a device mount /dev/xvdf /mnt/mongo and verify the mount using df-h:

Filesystem            Size  Used Avail Use% Mounted on  
/dev/xvda1            7.9G  955M  6.9G  12% /  
tmpfs                 299M   44K  299M   1% /dev/shm  
/dev/xvdf              20G  589M   19G   4% /mnt/mongo  

But now I'm trying to figure out how to make it auto mount on boot.

I understand I need to add a new entry to /etc/fstab, so I perform:

$ sed -i '$ a\/dev/xvdf /mnt/mongo xfs defaults 1 1' /etc/fstab

But, after reboot, it seems that the auto mount didn't work. The device didn't appear in the df -h list.

Should I not use the sed to add the entry? Is the entry I entered incorrect?

Answer 1

Sed is fine, but not ideal for what you're doing. Sed is more for when you just want a user to paste something to the terminal. Like the comments said, you can edit the file using nano or if you prefer the GUI you can use gedit, kate, or whatever your preferred editor is.

To get the filesystem to mount at boot, under the options field you want "auto" So your line should look like /dev/xvdf /mnt/mongo xfs defaults,auto 1 1