What is DRBD?
DRBD is an abbreviation of Distributed Replicated Block Device. DRBD is a block device which is designed to build high-availability clusters. This is done by mirroring a whole block device via (a dedicated) network. You could see it as a network RAID1.
I used two nodes with the following system settings:
1. cnode1.rnd (hostname) with the IP address 172.16.4.80. Operating system CentOS 4.5, two SCSI hard drives of 18 GB. Regarding partition I used the following scheme on cnode1.rnd:
/dev/sda1 / 13257MB ext3 primary
/dev/sda2 4095MB swap primary
/dev/sdb1 umounted 128MB ext3 primary (for DRBD’s meta data)
/dev/sdb2 umounted 4306MB ext3 primary (used as DRBD’s Disk)
2. cnode2.rnd (hostname) with the IP address 172.16.4.81. Operating system CentOS 4.5 one IDE drive of 10 GB. The following partition scheme was used on cnode2.rnd:
/dev/hda1 / 4503MB ext3 primary
/dev/hda2 769MB swap primary
/dev/hda3 unmounted 128MB ext3 primary (for DRBD’s meta data)
/dev/hda4 unmounted 4306MB ext3; primary (used as DRBD’s Disk)