GlusterFS

GlusterFS is a distributed filesystem. It has built in redundancy, so it is possible to run two servers which automatically replicate files between the servers. If one server goes down, the other just takes over. Once it comes up again, files are automatically replicated. Here we will use GlusterFS as a redundant network mounted file storage.

For the sport of it, we will configure 4 GlusterFS servers.

Network

The GlusterFS servers will have fixed IP-addresses. That is configured in the DHCP servers list of statically assigned IP-adresses by using the Domains MAC address.

Disk

We will add an additional disk to the system. This disk will be used for file storage.

Software

apt-get install glusterfs-server

from gluster01 connect with the other gluster servers 

gluster peer probe gluster02
gluster peer probe gluster03
gluster peer probe gluster04

check server status 

gluster peer status
Number of Peers: 3

Hostname: gluster02
Uuid: 031573c2-3b1f-4946-bd78-421563249db6
State: Peer in Cluster (Connected)

Hostname: gluster03
Uuid: ff5cec1c-6d7f-4db7-8676-08deff06b4d0
State: Peer in Cluster (Connected)

Hostname: gluster04
Uuid: 65fc398a-52e9-4292-9bbb-884becfbf5d6
State: Peer in Cluster (Connected)

on the kvm host

add a 16GiB harddisk for each of the servers 

lvcreate --size 16G --name kvm_gluster01_vdb vg2
lvcreate --size 16G --name kvm_gluster02_vdb vg2
lvcreate --size 16G --name kvm_gluster03_vdb vg2
lvcreate --size 16G --name kvm_gluster04_vdb vg2

hotadd those disks 

virsh attach-disk gluster01 --source /dev/vg2/kvm_gluster01_vdb --target vdb
virsh attach-disk gluster02 --source /dev/vg2/kvm_gluster02_vdb --target vdb
virsh attach-disk gluster03 --source /dev/vg2/kvm_gluster03_vdb --target vdb
virsh attach-disk gluster04 --source /dev/vg2/kvm_gluster04_vdb --target vdb

in the guest

create one large partition on vdb

pvcreate /dev/vdb1 vgcreate vg2 /dev/vdb1

create the volumes

lvcreate --size 4G --name gluster_www vg2 lvcreate --size 4G --name gluster_mail vg2

create the mountpoints

mkdir /srv/mail mkdir /srv/www

format the volumes mkfs.btrfs /dev/vg2/gluster_www mkfs.btrfs /dev/vg2/gluster_mail

add the volumes to /etc/fstab

/dev/vg2/gluster_www /srv/www btrfs defaults 0 0 /dev/vg2/gluster_mail /srv/mail btrfs defaults 0 0