drbd is a block device which is designed to build high availability clusters by mirroring a whole block device using a dedicated network. It can be seen as a network RAID-1.
To simplify a high availability configuration, the configuration scripts soft-link the configuration files for the DHCP and DNS service. For this reason, the DHCP daemon must not run in chroot(1) environments. Choose the configuration DHCPD\_RUN\_CHROOTED=’no’ in the /etc/sysconfig/dhcpd file.
The drbd.conf file is the configuration file for the drbd service. It defines the following parameters:
NOTE:These parameters are required to run drbd; additional parameters can be defined for fine tuning. For more information on these parameters, refer to the comments in the drbd.conf file.
Meta-disk is either “internal” or “/dev/ice/name [idx].”
You can use a single block device to store meta-data for multiple drbd’s. For example, use meta-disk /dev/hde6[0]; and meta-disk /dev/hde6[1]; for two different resources. In this case the meta-disk would need to be at least 256 MB in size.
“internal” means that the last 128 MB of the lower device are used to store the metadata.
NOTE:Do not give an index with “internal.”
The format of these parameters in the drbd.conf file is defined as follows:
on bs1 {
device /dev/drbd0;
disk /dev/hda3;
address 192.168.2.1:7788;
meta-disk internal;
}
on bs2 {
device /dev/drbd0;
disk /dev/hda3;
address 192.168.2.2:7788;
meta-disk internal;
}