There is a new version of this tutorial available for Ubuntu 18.04 (Bionic Beaver).

High-Availability Storage With GlusterFS 3.2.x On Ubuntu 11.10 - Automatic File Replication Across Two Storage Servers - Page 2

3 Setting Up The GlusterFS Client

client1.example.com:

On the client, we can install the GlusterFS client as follows:

apt-get install glusterfs-client

Then we create the following directory:

mkdir /mnt/glusterfs

That's it! Now we can mount the GlusterFS filesystem to /mnt/glusterfs with the following command:

mount -t glusterfs server1.example.com:/testvol /mnt/glusterfs

(Instead of server1.example.com you can as well use server2.example.com in the above command!)

You should now see the new share in the outputs of...

mount

[email protected]:~# mount
/dev/mapper/server3-root on / type ext4 (rw,errors=remount-ro)
proc on /proc type proc (rw,noexec,nosuid,nodev)
sysfs on /sys type sysfs (rw,noexec,nosuid,nodev)
fusectl on /sys/fs/fuse/connections type fusectl (rw)
none on /sys/kernel/debug type debugfs (rw)
none on /sys/kernel/security type securityfs (rw)
udev on /dev type devtmpfs (rw,mode=0755)
devpts on /dev/pts type devpts (rw,noexec,nosuid,gid=5,mode=0620)
tmpfs on /run type tmpfs (rw,noexec,nosuid,size=10%,mode=0755)
none on /run/lock type tmpfs (rw,noexec,nosuid,nodev,size=5242880)
none on /run/shm type tmpfs (rw,nosuid,nodev)
/dev/sda1 on /boot type ext2 (rw)
server1.example.com:/testvol on /mnt/glusterfs type fuse.glusterfs (rw,allow_other,default_permissions,max_read=131072)
[email protected]:~#

... and...

df -h

[email protected]:~# df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/mapper/server3-root
                       29G  1.1G   27G   4% /
udev                  238M  4.0K  238M   1% /dev
tmpfs                  99M  212K   99M   1% /run
none                  5.0M     0  5.0M   0% /run/lock
none                  247M     0  247M   0% /run/shm
/dev/sda1             228M   24M  193M  11% /boot
server1.example.com:/testvol
                       29G  1.1G   27G   4% /mnt/glusterfs
[email protected]:~#

Instead of mounting the GlusterFS share manually on the client, you could modify /etc/fstab so that the share gets mounted automatically when the client boots.

Open /etc/fstab and append the following line:

vi /etc/fstab

[...]
server1.example.com:/testvol /mnt/glusterfs glusterfs defaults,_netdev 0 0

(Again, instead of server1.example.com you can as well use server2.example.com!)

To test if your modified /etc/fstab is working, reboot the client:

reboot

After the reboot, you should find the share in the outputs of...

df -h

... and...

mount

 

4 Testing

Now let's create some test files on the GlusterFS share:

client1.example.com:

touch /mnt/glusterfs/test1
touch /mnt/glusterfs/test2

Now let's check the /data directory on server1.example.com and server2.example.com. The test1 and test2 files should be present on each node:

server1.example.com/server2.example.com:

ls -l /data

[email protected]:~# ls -l /data
total 8
-rw-r--r-- 1 root root 0 2012-04-02 11:17 test1
-rw-r--r-- 1 root root 0 2012-04-02 11:17 test2
[email protected]:~#

Now we shut down server1.example.com and add/delete some files on the GlusterFS share on client1.example.com.

server1.example.com:

shutdown -h now

client1.example.com:

touch /mnt/glusterfs/test3
touch /mnt/glusterfs/test4
rm -f /mnt/glusterfs/test2

The changes should be visible in the /data directory on server2.example.com:

server2.example.com:

ls -l /data

[email protected]:~# ls -l /data
total 8
-rw-r--r-- 1 root root 0 2012-04-02 11:17 test1
-rw-r--r-- 1 root root 0 2012-04-02 11:38 test3
-rw-r--r-- 1 root root 0 2012-04-02 11:38 test4
[email protected]:~#

Let's boot server1.example.com again and take a look at the /data directory:

server1.example.com:

ls -l /data

[email protected]:~# ls -l /data
total 8
-rw-r--r-- 1 root root 0 2012-04-02 11:17 test1
-rw-r--r-- 1 root root 0 2012-04-02 11:17 test2
[email protected]:~#

As you see, server1.example.com hasn't noticed the changes that happened while it was down. This is easy to fix, all we need to do is invoke a read command on the GlusterFS share on client1.example.com, e.g.:

client1.example.com:

ls -l /mnt/glusterfs/

[email protected]:~# ls -l /mnt/glusterfs/
total 8
-rw-r--r-- 1 root root 0 2012-04-02 11:17 test1
-rw-r--r-- 1 root root 0 2012-04-02 11:38 test3
-rw-r--r-- 1 root root 0 2012-04-02 11:38 test4
[email protected]:~#

Now take a look at the /data directory on server1.example.com again, and you should see that the changes have been replicated to that node:

server1.example.com:

ls -l /data

[email protected]:~# ls -l /data
total 4
-rw-r--r-- 1 root root 0 2012-04-02 11:17 test1
-rw-r--r-- 1 root root 0 2012-04-02 11:38 test3
-rw-r--r-- 1 root root 0 2012-04-02 11:38 test4
[email protected]:~#

 

Falko Timme

About Falko Timme

Falko Timme is an experienced Linux administrator and founder of Timme Hosting, a leading nginx business hosting company in Germany. He is one of the most active authors on HowtoForge since 2005 and one of the core developers of ISPConfig since 2000. He has also contributed to the O'Reilly book "Linux System Administration".

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