Setting Up A Highly Available NFS Server - Page 2

4 Install NFS Server

Next we install the NFS server on both server1 and server2:

server1/server2:

apt-get install nfs-kernel-server

Then we remove the system bootup links for NFS because NFS will be started and controlled by heartbeat in our setup:

server1/server2:

update-rc.d -f nfs-kernel-server remove
update-rc.d -f nfs-common remove

We want to export the directory /data/export (i.e., this will be our NFS share that our web server cluster nodes will use to serve web content), so we edit /etc/exports on server1 and server2. It should contain only the following line:

server1/server2:

/etc/exports:

/data/export/ 192.168.0.0/255.255.255.0(rw,no_root_squash,no_all_squash,sync)

This means that /data/export will be accessible by all systems from the 192.168.0.x subnet. You can limit access to a single system by using 192.168.0.100/255.255.255.255 instead of 192.168.0.0/255.255.255.0, for example. See

man 5 exports

to learn more about this.

Later in this tutorial we will create /data/exports on our empty (and still unmounted!) partition /dev/sda8.


5 Install DRBD

Next we install DRBD on both server1 and server2:

server1/server2:

apt-get install kernel-headers-2.6.8-2-386 drbd0.7-module-source drbd0.7-utils
cd /usr/src/
tar xvfz drbd0.7.tar.gz
cd modules/drbd/drbd
make
make install

Then edit /etc/drbd.conf on server1 and server2. It must be identical on both systems and looks like this:

server1/server2:

/etc/drbd.conf:

resource r0 {

protocol C;
incon-degr-cmd "halt -f";

startup {
degr-wfc-timeout 120; # 2 minutes.
}

disk {
on-io-error detach;
}

net {

}

syncer {

rate 10M;

group 1;

al-extents 257;
}

on server1 { # ** EDIT ** the hostname of server 1 (uname -n)
device /dev/drbd0; #
disk /dev/sda8; # ** EDIT ** data partition on server 1
address 192.168.0.172:7788; # ** EDIT ** IP address on server 1
meta-disk /dev/sda7[0]; # ** EDIT ** 128MB partition for DRBD on server 1
}

on server2 { # ** EDIT ** the hostname of server 2 (uname -n)
device /dev/drbd0; #
disk /dev/sda8; # ** EDIT ** data partition on server 2
address 192.168.0.173:7788; # ** EDIT ** IP address on server 2
meta-disk /dev/sda7[0]; # ** EDIT ** 128MB partition for DRBD on server 2
}

}

As resource name you can use whatever you like. Here it's r0. Please make sure you put the correct hostnames of server1 and server2 into /etc/drbd.conf. DRBD expects the hostnames as they are shown by the command

uname -n

If you have set server1 and server2 respectively as hostnames during the basic Debian installation, then the output of uname -n should be server1 and server2.

Also make sure you replace the IP addresses and the disks appropriately. If you use /dev/hda instead of /dev/sda, please put /dev/hda8 instead of /dev/sda8 into /etc/drbd.conf (the same goes for the meta-disk where DRBD stores its meta data). /dev/sda8 (or /dev/hda8...) will be used as our NFS share later on.

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From: Anonymous at: 2008-11-03 05:57:37
From: Clearjet at: 2009-06-29 15:53:39

The text says:

Also, make sure /dev/sda7 as well as /dev/sda8 are identical in size

But the illustration indicates:

/dev/sda7 -- 150 MB unmounted
/dev/sda8 -- 26 GB unmounted

So which is it?

Thanks

From: Anonymous at: 2009-07-03 11:50:05

Means same size on BOTH server in cluster.

From: gryger at: 2010-10-04 22:13:07

And here: http://docs.homelinux.org another well explained tutorial about DRBD and NFS on Debian.

From: Anonymous at: 2014-03-05 19:18:07

This is somewhat of the set-up that I have been looking for, however when joining this “Highly Available NFS Server or a Balanced MySQL Cluster” with a “Loadbalanced High-Availability Web Server Apache Cluster”, my concerns are the IP's...

The tutorial for both “Loadbalanced High-Availability MySQL Cluster and Loadbalanced High-Availability Web Server Apache Cluster” utilize the same IP addresses…

Within this tutorial it’s mentioned “Virtual IP address that represents the NFS cluster to the outside and also a NFS client IP address...”

I am looking to join two of the clusters to make a highly available stable web hosting cluster with utilizing either NFS or MySQL for the back-end…

Which IP’s should be used for each node?

From: Anonymous at: 2006-07-13 21:56:56

this may be pretty obvious, but when you install the kernel-headers  package, make sure you're using the version which match your running kernel (for example kernel-headers-2.6.8-2-686-smp ).

 

From: at: 2007-01-11 05:23:25

Yes, this is VERY IMPORTANT.

 When installing your kernel headers, simply do this:

apt-get install kernel-headers-`uname -r` drbd0.7-module-source drbd0.7-utils

 

The `uname -r` will automatically insert your proper kernel version into the command.

Try running the command uname -r once, by itself, to see.

From: Jason Priebe at: 2009-04-08 01:17:40

We considered the DRBD approach as well when we looked to replace our NetApp cluster with a linux-based solution.  We settled on a slightly different approach (using RHEL and Cluster Suite). I welcome you to read my blog post about it.

From: Anonymous at: 2006-03-26 22:06:50

with recent drbd utils (0.7.17), I had to do

drbdsetup /dev/drbd0 primary --do-what-I-say

From: Anonymous at: 2009-08-04 12:48:43

On version 8.0.14, I have to do :

drbdsetup /dev/drbd0 primary -o

From: Anonymous at: 2009-11-07 15:17:35

Using drbd8-ultils you should use:

 drbdadm -- --overwrite-data-of-peer  primary all

From: Anonymous at: 2009-11-07 15:18:27

Using drbd8-ultils you should use:

 drbdadm -- --overwrite-data-of-peer  primary all

From: Anonymous at: 2006-03-26 22:09:26

Also before doing mount -t ext3 /dev/drbd0 /data, you should of course create filesystem there

mkfs.ext3 /dev/drbd0

I suggest making XFS filesystem.

From: starzinger at: 2006-03-10 10:24:13

To enable automatic failback from server2 to server1, you need to put in the following:

/etc/heartbeat/ha.cf:

auto_failback on

From: Anonymous at: 2006-03-07 16:30:56

If I want the data to be available to the NFS machines themselves, do you recommend mounting the virtual IP on them?

From: at: 2011-01-19 12:58:53

I think that is the only way,

why we are trying to use nfs then?

In drdb just one node is active, you cant do changes on the pasive one.

 

From: Anonymous at: 2006-03-09 18:46:27

Thanks for your info, pretty interesting.

Just two questions:

- Why ext3 is your choice instead of reiserfs?

- Why are you using ip-alias instead of iproute2?

Thanks in advance.

From: Anonymous at: 2006-03-13 10:48:37

I've thought about doing this before, but using iSCSI and the built in /dev/md aka software RAID to link the devices together as a mirrored device. Since iSCSI is supposedly a more open standard and can be used with multiple operating systems it'll be easier to implement on non-Linux systems as well.

From: arkarwmh at: 2015-02-09 10:46:19

But how do i "Virtual Ip" over the 2 servers?