How to Create a storage pool and image using the Btrfs File System

How to Create a storage pool and image using the Btrfs File System

If multiple hard disks are attached to your Linux system, you do not need to use these disks as separate storage, using the Btrfs file system, we can easily combine multiple disks to create a storage pool. After the storage pool is configured, we can also enable the image function to avoid data loss caused by disk damage.

Although there is no GUI configuration program yet, we can easily create a Btrfs File System Using the command line to combine multiple hard disks.

Makefile Analysis of Btrfs in Linux File System

Kconfig Analysis of Btrfs in Linux File System

Application of Btrfs File System in CentOS

What is Btrfs?

Btrfs is also called B-tree file system, Butter FS or Better FS. It integrates many different functions and features at the file system level. Although Btrfs file systems have many features worth our attention (such as file system snapshots), this article only explores the storage pool and image functions of Btrfs file systems.

Although the Btrfs file system is not recognized as "secure" by enterprise applications, its stability can meet the stability requirements of individual users. In the future, Btrfs will become the default file system format in Linux. If you only use a single disk or do not need new features such as Btrfs snapshots, storage pools, and images, it is better to use the ext4 file system.

Sample Environment

In this example, we will use four disks for demonstration, of which two are 1 TB disks (/dev/sdb and/dev/sdc respectively ), the remaining two disks are 500 GB (/dev/sdd and/dev/sde respectively), with a total storage space of 3 TB.

Create a Btrfs File System

To create a Btrfs file system, run the following command:

Sudo mkfs. btrfs/dev/sdb

Of course, you can replace/dev/sdb with your own disk in your own environment. Now we can create another disk as a Btrfs file system, but first we can use the following command to mount/dev/sdb to/mnt:

Sudo mount/dev/sdb/mnt

Then execute:

Sudo mkfs. btrfs/dev/sdc

Sudo mkfs. btrfs/dev/sdd

Sudo mkfs. btrfs/dev/sde

Now, we can add the above three magnetic disks to the/mnt directory:

Sudo btrfs device add/dev/sdc/mnt

Sudo btrfs device add/dev/sdd/mnt

Sudo btrfs device add/dev/sde/mnt

If you plan to use Btrfs to create a file system across multiple hard disks in advance, you can directly use the following command:

Sudo mkfs. btrfs-d single/dev/sdb/dev/sdc/dev/sdd/dev/sde

Now, the above-d single parameter indicates that we will create a Raid0 volume. Of course, we can also use the-d raid1 parameter to create a Raid1 volume. Even to use the-d raid10 parameter to create a Raid10 volume, this will convert our two 1 TB disk images into 1 TB, and the two 500 GB disk images into 500 GB, finally, merge the 1.5 TB available space.

If the disk fails

If a disk fails, we need to remove it from the file system so that the remaining disk can work normally. In this case, run the following command:

Sudo mount-o degraded/dev/sdb/mnt

Then run the following command to repair the file system:

Sudo btrfs device delete missing/mnt

If RAID1 or RAID10 is not enabled, data on the hard disk will be lost after the disk is damaged.

Btrfs details: click here
Btrfs: click here

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