Distributed Replicated Storage Across Four Storage Nodes With GlusterFS On CentOS 5.4
This tutorial shows how to combine four single storage servers (running CentOS 5.4) to a distributed replicated storage with GlusterFS. Nodes 1 and 2 (replication1) as well as 3 and 4 (replication2) will mirror each other, and replication1 and replication2 will be combined to one larger storage server (distribution). Basically, this is RAID10 over network. If you lose one server from replication1 and one from replication2, the distributed volume continues to work. The client system (CentOS 5.4 as well) will be able to access the storage as if it was a local filesystem. GlusterFS is a clustered file-system capable of scaling to several peta-bytes. It aggregates various storage bricks over Infiniband RDMA or TCP/IP interconnect into one large parallel network file system. Storage bricks can be made of any commodity hardware such as x86_64 servers with SATA-II RAID and Infiniband HBA.
I do not issue any guarantee that this will work for you!
1 Preliminary Note
In this tutorial I use five systems, four servers and a client:
- server1.example.com: IP address 192.168.0.100 (server)
- server2.example.com: IP address 192.168.0.101 (server)
- server3.example.com: IP address 192.168.0.102 (server)
- server4.example.com: IP address 192.168.0.103 (server)
- client1.example.com: IP address 192.168.0.104 (client)
All five systems should be able to resolve the other systems' hostnames. If this cannot be done through DNS, you should edit the /etc/hosts file so that it contains the following lines on all five systems:
[...] 192.168.0.100 server1.example.com server1 192.168.0.101 server2.example.com server2 192.168.0.102 server3.example.com server3 192.168.0.103 server4.example.com server4 192.168.0.104 client1.example.com client1 [...]
(It is also possible to use IP addresses instead of hostnames in the following setup. If you prefer to use IP addresses, you don't have to care about whether the hostnames can be resolved or not.)
2 Setting Up The GlusterFS Servers
GlusterFS isn't available as a package for CentOS 5.4, therefore we have to build it ourselves. First we install the prerequisites:
yum groupinstall 'Development Tools'
yum groupinstall 'Development Libraries'
yum install libibverbs-devel fuse-devel
Then we download the latest GlusterFS release from http://www.gluster.org/download.php and build it as follows:
tar xvfz glusterfs-2.0.9.tar.gz
At the end of the ./configure command, you should see something like this:
GlusterFS configure summary
FUSE client : yes
Infiniband verbs : yes
epoll IO multiplex : yes
Berkeley-DB : yes
libglusterfsclient : yes
argp-standalone : no
[[email protected] glusterfs-2.0.9]#
make && make install
Check the GlusterFS version afterwards (should be 2.0.9):
[[email protected] glusterfs-2.0.9]# glusterfs --version
glusterfs 2.0.9 built on Mar 1 2010 15:34:50
Repository revision: v2.0.9
Copyright (c) 2006-2009 Gluster Inc. <http://www.gluster.com>
GlusterFS comes with ABSOLUTELY NO WARRANTY.
You may redistribute copies of GlusterFS under the terms of the GNU General Public License.
[[email protected] glusterfs-2.0.9]#
Next we create a few directories:
Now we create the GlusterFS server configuration file /etc/glusterfs/glusterfsd.vol which defines which directory will be exported (/data/export) and what client is allowed to connect (192.168.0.104 = client1.example.com):
volume posix type storage/posix option directory /data/export end-volume volume locks type features/locks subvolumes posix end-volume volume brick type performance/io-threads option thread-count 8 subvolumes locks end-volume volume server type protocol/server option transport-type tcp option auth.addr.brick.allow 192.168.0.104 subvolumes brick end-volume
Please note that it is possible to use wildcards for the IP addresses (like 192.168.*) and that you can specify multiple IP addresses separated by comma (e.g. 192.168.0.104,192.168.0.105).
Afterwards we create the following symlink...
ln -s /usr/local/sbin/glusterfsd /sbin/glusterfsd
... and then the system startup links for the GlusterFS server and start it:
chkconfig --levels 35 glusterfsd on