Attaching a EBS Volume to EC2

Question

I followed the steps as described on http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/ec2-add-volume-to-instance.html

It worked well until the last point. I get the following error

root@ip-10-134-145-102:/home/ubuntu/crsq# mount -a
mount: special device /dev/xvdb does not exist

My file system is as follows:

root@ip-10-134-145-102:/home/ubuntu/crsq# df -h
Filesystem      Size  Used Avail Use% Mounted on
/dev/xvda1      7.9G  4.2G  3.4G  56% /
udev            819M   12K  819M   1% /dev
tmpfs           331M  184K  331M   1% /run
none            5.0M     0  5.0M   0% /run/lock
none            827M     0  827M   0% /run/shm
/dev/xvdf        99G  188M   94G   1% /mnt/dbmount

The final fstab file is as follows:

root@ip-10-134-145-102:/home/ubuntu/crsq# cat /etc/fstab
LABEL=cloudimg-rootfs   /    ext4   defaults    0 0
/dev/xvdb   /mnt    auto    defaults,nobootwait,comment=cloudconfig 0   2
/dev/xvda3  none    swap    sw,comment=cloudconfig  0   0
/dev/xvdf       /mnt/dbmount   ext4    defaults        0       2

The original fstab file is as:

root@ip-10-134-145-102:/home/ubuntu/crsq# cat /etc/fstab.orig 
LABEL=cloudimg-rootfs   /    ext4   defaults    0 0
/dev/xvdb   /mnt    auto    defaults,nobootwait,comment=cloudconfig 0   2
/dev/xvda3  none    swap    sw,comment=cloudconfig  0   0

Answer 1

The error message is just saying that /dev/xvdb more than likely you are using an fstab from an instance that had an ephemeral storage as /dev/xvdb. Regardless, that message should not affect the mounting of /dev/xvdf which is the EBS Volume that you want to mount. -- You can even see it when you run df -h.

To remove the /dev/xvdb message you can just remove the line containing /dev/xvdb from your fstab file.