AWS ESB 磁盘 动态扩容 （我测试过该步骤）

Say we want to increase boot drive of Ubuntu from 8G up to 16G "on-the-fly".

step-1) login into AWS web console -> EBS -> right mouse click on the one you wish to resize -> "Modify Volume" -> change "Size" field and click [Modify] button

step-2) ssh into the instance and resize the partition: 

let's list block devices attached to our box:

lsblk
NAME    MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
xvda    202:0    0  16G  0 disk
└─xvda1 202:1    0   8G  0 part /
           

As you can see /dev/xvda1 is still 8 GiB partition on a 16 GiB device and there are no other partitions on the volume. Let's use "growpart" to resize 8G partition up to 16G:

# install "cloud-guest-utils" if it is not installed already
apt install cloud-guest-utils

# resize partition
growpart /dev/xvda 1
           

Let's check the result (you can see /dev/xvda1 is now 16G):

lsblk
NAME    MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
xvda    202:0    0  16G  0 disk
└─xvda1 202:1    0  16G  0 part /
           

Lots of SO answers suggest to use fdisk with delete / recreate partitions, which is nasty, risky, error-prone process especially when we change boot drive.

step-3) resize file system to grow all the way to fully use new partition space

# Check before resizing ("Avail" shows 1.1G):
df -h
Filesystem      Size  Used Avail Use% Mounted on
/dev/xvda1      7.8G  6.3G  1.1G  86% /

# resize filesystem
resize2fs /dev/xvda1

# Check after resizing ("Avail" now shows 8.7G!-):
df -h
Filesystem      Size  Used Avail Use% Mounted on
/dev/xvda1       16G  6.3G  8.7G  42% /
           

So we have zero downtime and lots of new space to use.