Adding devices to the btrfs filesystem

We have already seen a little of volume management using LVM when we looked at iSCSI in Chapter 4, Implementing iSCSI SANs, and it's not exactly simple.

Volume management the old way

The following commands are used in order to manage the disk volumes in the old, traditional way:

# pvcreate /dev/sde1
# vgextend vg1 /dev/sde1
# lvextend -L+1000M /dev/vg1/data_lv
# resize2fs /dev/vg1/data

Volume management with btrfs

To start with, we will return the volume back to its original size before we add the second disk. Using the max option, we will ensure that the btrfs filesystem uses the maximum space available on the single disk we have in place so far:

# btrfs filesystem resize max /data/simple

In LVM and traditional filesystems, there were a total of four commands to be executed. In btrfs, we can perform this with a single command:

# btrfs device add /dev/sde /data/simple

This is all we need to do. The device is added and the filesystem is automatically increased...