GlusterFS: Tutorial & Best Practices

A distributed file system

GlusterFS is a free and open-source distributed file system that allows you to create a single, unified filesystem from multiple storage servers. It is designed to provide scalable, high-performance storage for applications that require large amounts of data.

GlusterFS works by distributing data across multiple storage servers, and it uses algorithms to optimize the placement of data on the servers based on various factors such as performance, capacity, and availability. It also uses replication and self-healing mechanisms to ensure data integrity and availability.

To use GlusterFS, you will need to install the GlusterFS software on multiple servers and configure them to form a storage pool. You can then create a filesystem on top of the storage pool and mount it on your client machines.

GlusterFS is a powerful and flexible tool for managing large-scale storage in distributed environments, and it is widely used in organizations and businesses to improve the performance and scalability of their storage systems.

Set up a firewall so that all servers can communicate with each other over a secure VPN.

To install and configure GlusterFS under Linux, you will need to follow these steps:

Install GlusterFS: To install GlusterFS on a Debian-based system (such as Ubuntu), you can use the following command:
```
sudo apt-get update && sudo apt-get install glusterfs-server
```
To install GlusterFS on a Red Hat-based system (such as CentOS), you can use the following command:
```
sudo yum install glusterfs-server
```
Create a storage pool: To create a storage pool with GlusterFS, you will need to install the GlusterFS software on multiple servers and configure them to form a pool. You can do this using the gluster peer probe command.

For example, to add server2 to a storage pool that already contains server1, you can use the following command on server1:
```
sudo gluster peer probe server2
```
You can then use the gluster peer status command to view the status of the storage pool.
Create a filesystem: Once you have created a storage pool, you can create a GlusterFS filesystem on top of it. To do this, you will need to specify the servers and the directory that will be used to store the data.

For example, to create a filesystem that uses the /data directory on server1 and server2, you can use the following command on server1:
```
sudo gluster volume create myvol server1:/data server2:/data
```
This will create a new GlusterFS volume called "myvol" that is distributed across the two servers.
Start the filesystem: To start the GlusterFS filesystem, you can use the gluster volume start command. For example, to start the "myvol" volume that you created in step 3, you can use the following command:
```
sudo gluster volume start myvol
```
Mount the filesystem: To access the GlusterFS filesystem from a client machine, you will need to mount it. To do this, you can use the mount command with the -t glusterfs option.

For example, to mount the "myvol" volume on the /mnt directory on a client machine, you can use the following command:
```
sudo mount -t glusterfs server1:/myvol /mnt
```
This will mount the "myvol" volume on the client machine, and you will be able to access the files and directories in the volume as if they were local files.
Configure automatic mounting: To configure the GlusterFS filesystem to be automatically mounted when the client machine starts up, you will need to add an entry to the /etc/fstab file.

For example, to automatically mount the "myvol" volume on the /mnt directory, you can add the following line to the /etc/fstab file:
```
server1:/myvol /mnt glusterfs defaults 0 0
```
This will cause the "myvol" volume to be automatically mounted when the client machine starts up.

Add the gpg key for the GlusterFS repository:

wget -O - http://download.gluster.org/pub/gluster/glusterfs/3.3/3.3.1/Debian/gpg.key | apt-key add -

Add the repository to your system by adding this line:

deb http://download.gluster.org/pub/gluster/glusterfs/3.3/3.3.1/Debian/wheezy.repo wheezy main

Now we can install the GlusterFS server:

apt-get update
apt-get install glusterfs-server

Configure to use the appropriate IP address in /etc/glusterfs/glusterd.vol:

volume management
type mgmt/glusterd
option working-directory /etc/glusterd
option transport-type socket
option transport.socket.keepalive-time 10
option transport.socket.keepalive-interval 2
option transport.rdma.bind-address 10.0.0.1
option transport.socket.bind-address 10.0.0.1
option transport.tcp.bind-address 10.0.0.1
end-volume

Restart the service:

/etc/init.d/glusterfs-server restart

Take a look at the current cluster:

gluster --remote-host=10.0.0.1 peer status

There are no peers present yet, so let's add one:

gluster --remote-host=10.0.0.1 peer probe
gluster --remote-host=10.0.0.1 peer status

Here are some more peers:

Number of Peers: 2

Hostname: 10.0.0.2
Uuid: ffeaccb6-00ad-488c-9f53-7b215a059d81
State: Peer in Cluster (Connected)

Hostname: 10.0.0.3
Uuid: 46b50830-03b9-4040-934a-a9da78708543
State: Peer in Cluster (Connected)
Ready to mount the file system:

Mount a volume:

mount -t glusterfs 10.0.0.1:/vol /mnt/vol

Take a look at the status:

gluster --remote-host=10.0.0.1 volume info
gluster --remote-host=10.0.0.1 peer status