Attaching Volume to an instance
NOTE: This is a repost from my blog
A volume is like a hard disk attached to your system. First create a volume and attach it to your instance.
Finding/Verifying attached volume
Option 1:
Output should look something like this:
user@host $ sudo lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
xvda 202:0 0 48G 0 disk
└─xvda1 202:2 0 48G 0 part /
xvdf 202:80 0 50G 0 disk /mnt/mongo_data
xvdg 202:96 0 500G 0 disk
If you see the output closely, you can see that xvda is a disk with xvda1 partition mounted at root (/).
Similarly xvdg is a freshly added partition.
Option 2:
Output:
Disk /dev/xvda: 48 GiB, 51539607552 bytes, 100663296 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 Disklabel type: gpt Disk identifier: A285F90B-B6D2-4DFB-BB36-CFCA7E815241
Device Start End Sectors Size Type /dev/xvda1 34 100663262 100661214 48G Linux filesystem
Disk /dev/xvdf: 50 GiB, 53687091200 bytes, 104857600 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 _ /dev/xvdg _: 500 GiB, 536870912000 bytes, 1048576000 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
You can also see here the device name for fresh 500GB partition is /dev/xvdg as shown in 4th line from bottom. Note down this device name, you’ll need it in next steps.
Formatting a freshly attached partition:
- Find the identifier as mentioned above
sudo fdisk /dev/xvdg # After this command you will be prompted, press following commands followed by enter key
Welcome to fdisk (util-linux 2.25.2). Changes will remain in memory only, until you decide to write them. Be careful before using the write command.
Device does not contain a recognized partition table. Created a new DOS disklabel with disk identifier 0x17fef037.
Command (m for help): > Partition type p primary (0 primary, 0 extended, 4 free) e extended (container for logical partitions) > Partition number (1-4, default 1): > First sector (2048-1048575999, default 2048):
Last sector, +sectors or +size{K,M,G,T,P} (2048-1048575999, default 1048575999): > Created a new partition 1 of type ‘Linux’ and of size 500 GiB.
Command (m for help):
w # write table to disk and exit
This will apply the changes to disk and exit.
Now we format the partition
sudo mkfs.ext4 /dev/xvdg1
Mounting on every boot
Adding to fstab
/dev/xvda1: LABEL=”cloudimg-rootfs” UUID=”ae0adbc7-8703-4e7e-8d8d-eead38e0578f” TYPE=”ext4” /dev/xvdg1 : UUID=” b38e5f52-6aed-43ae-80dd-9eb8246a1511 ” TYPE=”ext4”
Edit the fstab file. Use the UUID mentioned above
LABEL=cloudimg-rootfs / ext4 defaults 0 0_UUID=b38e5f52-6aed-43ae-80dd-9eb8246a1511 /home/admin/path/new_disk ext4 defaults 0 0_
As per the man page defaults options are: rw, suid, dev, exec, auto, nouser, and async.
Read more about fstab here
Mounting partition one-time
mkdir /home/admin/path/new_disk
sudo mount /dev/xvdg1 /home/admin/path/new_disk
See if you can access file in new partition:
ls -l /home/admin/path/new_disk
Verifying final partition table
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT xvda 253:0 0 50G 0 disk └─xvda1 253:1 0 50G 0 part / xvdg 253:16 0 500G 0 disk └─xvdg1 253:17 0 500G 0 part /home/admin/path/new_disk
