Attaching and mounting existing EBS volume to EC2 instance filesystem issue Attaching and mounting existing EBS volume to EC2 instance filesystem issue linux linux

Attaching and mounting existing EBS volume to EC2 instance filesystem issue


The One Liner


🥇 Mount the partition (if disk is partitioned):

sudo mount /dev/xvdf1 /vol -t ext4

Mount the disk (if not partitioned):

sudo mount /dev/xvdf /vol -t ext4

where:

  • /dev/xvdf is changed to the EBS Volume device being mounted
  • /vol is changed to the folder you want to mount to.
  • ext4 is the filesystem type of the volume being mounted

Common Mistakes How To:


✳️ Attached Devices List

Check your mount command for the correct EBS Volume device name and filesystem type. The following will list them all:

sudo lsblk --output NAME,TYPE,SIZE,FSTYPE,MOUNTPOINT,UUID,LABEL

If your EBS Volume displays with an attached partition, mount the partition; not the disk.


✳️ If your volume isn't listed

If it doesn't show, you didn't Attach your EBS Volume in AWS web-console


✳️ Auto Remounting on Reboot

These devices become unmounted again if the EC2 Instance ever reboots.

A way to make them mount again upon startup is to add the volume to the server's /etc/fstab file.

🔥 Caution:🔥
If you corrupt the /etc/fstab file, it will make your system unbootable. Read AWS's short article so you know to check that you did it correctly.

https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/ebs-using-volumes.html#ebs-mount-after-reboot

First:
With the lsblk command above, find your volume's UUID & FSTYPE.

Second:
Keep a copy of your original fstab file.

sudo cp /etc/fstab /etc/fstab.original

Third:
Add a line for the volume in sudo nano /etc/fstab.

The fields of fstab are 'tab-separated' and each line has the following fields:

<UUID>  <MOUNTPOINT>    <FSTYPE>    defaults,discard,nofail 0   0

Here's an example to help you, my own fstab reads as follows:

LABEL=cloudimg-rootfs   /   ext4    defaults,discard,nofail 0   0UUID=e4a4b1df-cf4a-469b-af45-89beceea5df7   /var/www-data   ext4    defaults,discard,nofail 0   0

That's it, you're done. Check for errors in your work by running:

sudo mount --all --verbose

You will see something like this if things are 👍:

/                   : ignored/var/www-data       : already mounted


I noticed that for some reason the volume was located at /dev/xvdf1, not /dev/xvdf.

Using

sudo mount /dev/xvdf1 /vol -t ext4

worked like a charm


I encountered this problem too after adding a new 16GB volume and attaching it to an existing instance. First of all you need to know what disks you have presentRun

  sudo fdisk -l 

You'll' have an output that appears like the one shown below detailing information about your disks (volumes"

 Disk /dev/xvda: 12.9 GB, 12884901888 bytes  255 heads, 63 sectors/track, 1566 cylinders, total 25165824 sectors  Units = sectors of 1 * 512 = 512 bytes  Sector size (logical/physical): 512 bytes / 512 bytes  I/O size (minimum/optimal): 512 bytes / 512 bytes  Disk identifier: 0x00000000Device Boot      Start         End      Blocks   Id  System/dev/xvda1   *       16065    25157789    12570862+  83  Linux Disk /dev/xvdf: 17.2 GB, 17179869184 bytes 255 heads, 63 sectors/track, 2088 cylinders, total 33554432 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000 Disk /dev/xvdf doesn't contain a valid partition table

As you can see the newly added Disk /dev/xvdf is present. To make it available you need to create a filesystem on it and mount it to a mount point. You can achieve that with the following commands

 sudo mkfs -t ext4 /dev/xvdf

Making a new file system clears everything in the volume so do this on a fresh volume without important data

Then mount it maybe in a directory under the /mnt folder

 sudo mount /dev/xvdf /mnt/dir/

Confirm that you have mounted the volume to the instance by running

  df -h

This is what you should have

Filesystem      Size  Used Avail Use% Mounted on udev            486M   12K  486M   1% /dev tmpfs           100M  400K   99M   1% /run /dev/xvda1       12G  5.5G  5.7G  50% / none            4.0K     0  4.0K   0% /sys/fs/cgroup none            5.0M     0  5.0M   0% /run/lock none            497M     0  497M   0% /run/shm none            100M     0  100M   0% /run/user /dev/xvdf        16G   44M   15G   1% /mnt/ebs

And that's it you have the volume for use there attached to your existing instance.credit