MySQL 備援 – DRDB

http://www.drbd.org/

DRBD^® refers to block devices designed as a building block to form high availability (HA) clusters.
This is done by mirroring a whole block device via an assigned network. It is shown as network raid-1- DRBD.

In the illustration above, the two orange boxes represent two servers that form an HA cluster.
The boxes contain the usual components of a Linux™ kernel: file system, buffer cache, disk scheduler, disk drivers, TCP/IP stack and network interface card (NIC) driver.
The black arrows illustrate the flow of data between these components.

The orange arrows show the flow of data, as DRBD mirrors the data of a high availably service from the active node of the HA cluster to the standby node of the HA cluster.

http://wiselysong.blogspot.com/2009/01/heartbeatdrbdmysql-on-debian-etch.html

DRBD (Distributed Replicated Block Device) http://www.drbd.org/
是透過網路即時同步的Block Device,可視同為透過網路進行即時同步的Raid-1

DRBD搭配HeartBeat可建構高可用性(HA-high availability)的服務
如將MySQL的DATA FILE放到DRBD上,配合HeartBeat控管可作到MySQL高可用性的即時同步與Failover備援切換.