High-Availability Storage With GlusterFS On Debian Lenny - Automatic File Replication Across Two Storage Servers

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Submitted by falko (Contact Author) (Forums) on Sun, 2009-06-07 17:59. :: Debian | High-Availability High-Availability Storage With GlusterFS On Debian Lenny - Automatic File Replication (Mirror) Across Two Storage Servers Version 1.0 Author: Falko Timme <ft [at] falkotimme [dot] com> Last edited 06/02/2009 This tutorial shows how to set up a high-availability storage with two storage servers (Debian Lenny) that use GlusterFS. Each storage server will be a mirror of the other storage server, and files will be replicated automatically across both storage servers. The client system (Debian Lenny 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 three systems, two servers and a client: server1.example.com: IP address 192.168.0.100 (server) server2.example.com: IP address 192.168.0.101 (server) client1.example.com: IP address 192.168.0.102 (client) All three 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 looks as follows on all three systems: vi /etc/hosts 127.0.0.1 localhost.localdomain localhost 192.168.0.100 server1.example.com server1 192.168.0.101 server2.example.com server2 192.168.0.102 client1.example.com client1 # The following lines are desirable for IPv6 capable hosts ::1 localhost ip6-localhost ip6-loopback fe00::0 ip6-localnet ff00::0 ip6-mcastprefix ff02::1 ip6-allnodes ff02::2 ip6-allrouters ff02::3 ip6-allhosts (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 server1.example.com/server2.example.com: GlusterFS isn't available as a Debian package for Debian Lenny, therefore we have to build it ourselves. First we install the prerequisites: aptitude install sshfs build-essential flex bison byacc libdb4.6 libdb4.6-dev Then we download the latest GlusterFS release from http://www.gluster.org/download.php and build it as follows: cd /tmp wget http://ftp.gluster.com/pub/gluster/glusterfs/2.0/LATEST/glusterfs-2.0.1.tar.gz tar xvfz glusterfs-2.0.1.tar.gz cd glusterfs-2.0.1 ./configure --prefix=/usr > /dev/null server1:/tmp/glusterfs-2.0.1# ./configure --prefix=/usr > /dev/null GlusterFS configure summary =========================== FUSE client        : no Infiniband verbs   : no epoll IO multiplex : yes Berkeley-DB        : yes libglusterfsclient : yes mod_glusterfs      : no () argp-standalone    : no server1:/tmp/glusterfs-2.0.1# make && make install ldconfig The command glusterfs --version should now show the GlusterFS version that you've just compiled (2.0.1 in this case): server1:/tmp/glusterfs-2.0.1# glusterfs --version glusterfs 2.0.1 built on May 29 2009 17:23:10 Repository revision: 5c1d9108c1529a1155963cb1911f8870a674ab5b Copyright (c) 2006-2009 Z RESEARCH Inc. <http://www.zresearch.com> GlusterFS comes with ABSOLUTELY NO WARRANTY. You may redistribute copies of GlusterFS under the terms of the GNU General Public License. server1:/tmp/glusterfs-2.0.1# Next we create a few directories: mkdir /data/ mkdir /data/export mkdir /data/export-ns mkdir /etc/glusterfs 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 (192.168.0.102 = client1.example.com): vi /etc/glusterfs/glusterfsd.vol 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 192.168.0.102 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. 192.168.0.102,192.168.0.103). Afterwards we create the system startup links for the glusterfsd init script... update-rc.d glusterfsd defaults ... and start glusterfsd: /etc/init.d/glusterfsd start 3 Setting Up The GlusterFS Client client1.example.com: On the client, we need to install fuse and GlusterFS. Instead of installing the libfuse2 package from the Debian repository, we install a patched version with better support for GlusterFS. First we install the prerequisites again: aptitude install sshfs build-essential flex bison byacc libdb4.6 libdb4.6-dev Then we build fuse as follows (you can find the latest patched fuse version on ftp://ftp.zresearch.com/pub/gluster/glusterfs/fuse/): cd /tmp wget ftp://ftp.zresearch.com/pub/gluster/glusterfs/fuse/fuse-2.7.4glfs11.tar.gz tar -zxvf fuse-2.7.4glfs11.tar.gz cd fuse-2.7.4glfs11 ./configure make && make install Afterwards we build GlusterFS (just like on the server)... cd /tmp wget http://ftp.gluster.com/pub/gluster/glusterfs/2.0/LATEST/glusterfs-2.0.1.tar.gz tar xvfz glusterfs-2.0.1.tar.gz cd glusterfs-2.0.1 ./configure --prefix=/usr > /dev/null make && make install ldconfig glusterfs --version ... and create the following two directories: mkdir /mnt/glusterfs mkdir /etc/glusterfs Next we create the file /etc/glusterfs/glusterfs.vol: vi /etc/glusterfs/glusterfs.vol volume remote1 type protocol/client option transport-type tcp option remote-host server1.example.com option remote-subvolume brick end-volume volume remote2 type protocol/client option transport-type tcp option remote-host server2.example.com option remote-subvolume brick end-volume volume replicate type cluster/replicate subvolumes remote1 remote2 end-volume volume writebehind type performance/write-behind option window-size 1MB subvolumes replicate end-volume volume cache type performance/io-cache option cache-size 512MB subvolumes writebehind end-volume Make sure you use the correct server hostnames or IP addresses in the option remote-host lines! That's it! Now we can mount the GlusterFS filesystem to /mnt/glusterfs with one of the following two commands: glusterfs -f /etc/glusterfs/glusterfs.vol /mnt/glusterfs or mount -t glusterfs /etc/glusterfs/glusterfs.vol /mnt/glusterfs You should now see the new share in the outputs of... mount client1:/tmp/glusterfs-2.0.1# mount /dev/sda1 on / type ext3 (rw,errors=remount-ro) tmpfs on /lib/init/rw type tmpfs (rw,nosuid,mode=0755) proc on /proc type proc (rw,noexec,nosuid,nodev) sysfs on /sys type sysfs (rw,noexec,nosuid,nodev) udev on /dev type tmpfs (rw,mode=0755) tmpfs on /dev/shm type tmpfs (rw,nosuid,nodev) devpts on /dev/pts type devpts (rw,noexec,nosuid,gid=5,mode=620) fusectl on /sys/fs/fuse/connections type fusectl (rw) /etc/glusterfs/glusterfs.vol on /mnt/glusterfs type fuse.glusterfs (rw,max_read=131072,allow_other,default_permissions) client1:/tmp/glusterfs-2.0.1# ... and... df -h client1:/tmp/glusterfs-2.0.1# df -h Filesystem            Size  Used Avail Use% Mounted on /dev/sda1              29G  935M   27G   4% / tmpfs                 126M     0  126M   0% /lib/init/rw udev                   10M   80K   10M   1% /dev tmpfs                 126M     0  126M   0% /dev/shm /etc/glusterfs/glusterfs.vol                        19G  804M   17G   5% /mnt/glusterfs client1:/tmp/glusterfs-2.0.1# (server1.example.com and server2.example.com each have 19GB of space for the GlusterFS filesystem, but because the data is mirrored, the client doesn't see 38GB (2 x 19GB), but only 19GB.) 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 [...] /etc/glusterfs/glusterfs.vol /mnt/glusterfs glusterfs defaults 0 0 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/export 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/export server1:~# ls -l /data/export total 0 -rw-r--r-- 1 root root 0 2009-06-02 15:31 test1 -rw-r--r-- 1 root root 0 2009-06-02 15:32 test2 server1:~# 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/export directory on server2.example.com: server2.example.com: ls -l /data/export server2:/tmp/glusterfs-2.0.1# ls -l /data/export total 0 -rw-r--r-- 1 root root 0 2009-06-02 15:31 test1 -rw-r--r-- 1 root root 0 2009-06-02 15:32 test3 -rw-r--r-- 1 root root 0 2009-06-02 15:33 test4 server2:/tmp/glusterfs-2.0.1# Let's boot server1.example.com again and take a look at the /data/export directory: server1.example.com: ls -l /data/export server1:~# ls -l /data/export total 0 -rw-r--r-- 1 root root 0 2009-06-02 15:31 test1 -rw-r--r-- 1 root root 0 2009-06-02 15:32 test2 server1:~# 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/ client1:~# ls -l /mnt/glusterfs/ total 0 -rw-r--r-- 1 root root 0 2009-06-02 15:31 test1 -rw-r--r-- 1 root root 0 2009-06-02 15:32 test3 -rw-r--r-- 1 root root 0 2009-06-02 15:33 test4 client1:~# Now take a look at the /data/export 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/export server1:~# ls -l /data/export total 0 -rw-r--r-- 1 root root 0 2009-06-02 15:31 test1 -rw-r--r-- 1 root root 0 2009-06-02 15:52 test3 -rw-r--r-- 1 root root 0 2009-06-02 15:52 test4 server1:~#   5 Links GlusterFS: http://www.gluster.org/ Debian: http://www.debian.org/ previous   up High-Availability Storage With GlusterFS On Debian Lenny - Automatic File Replication Across Two Storage Servers