Drbd

FromDual has released today the next version v0.6 of its FromDual Performance Monitor for MySQL.

The most important improvement of the new release is the new monitoring module for DRBD devices which are often used in MySQL High Availability (HA) set-ups.

More information about the new functionality added you can find in the article MySQL Performance Monitor with DRBD monitoring capabilities, MySQL Performance Monitor and in the MySQL HA (high availability) cookbook.

The FromDual Performance Monitor for …

In the following article I have summarized some steps and hints to set-up a MySQL active/passive failover Cluster also sometimes called MySQL HA.

With such a set-up you can achieve a 99.99% (4x9) HA set-up for MySQL (52 minutes downtime per year). The same procedure also works for PostgreSQL, Oracle and other database systems running on Linux (DRBD runs on Linux only).

The concept

The concept of an active/passive failover Cluster is the following:

• You have 2 servers (also called nodes).
• They communicate …

The FromDual Performance Monitor for MySQL has now a new module for monitoring DRBD. Since more an more of our customers want to run MySQL High Availability solutions based on DRBD we have implemented this module.

We gather all information which are reported with the command:

# cat /proc/drbd

version: 8.3.8 (api:88/proto:86-94)
 0: cs:Connected ro:Secondary/Primary ds:UpToDate/UpToDate C r----
    ns:1241240 nr:14311680 dw:15033532 dr:1241281 al:198 bm:52 lo:0 pe:0 ua:0
    ap:0 ep:1 wo:b oos:0

Now you …

The following solutions are used with MySQL:

• Redhat Cluster Suite (RHCS)
• SteelEye LiefKeeper
• Heartbeat (from the Linux HA project), Using Linux HA Heartbeat
• Crossroads
• Failover
• DRBD, Using MySQL with DRBD
• MySQL Cluster

Or an active-active failover cluster à la VMware.

Today I have learned about a totally crazy/cool looking architecture where the expensive VMware ESX server was replace by a free/cheap VMware Workstation version in combination with DRBD.

Basically DRBD we name the poor man’s SAN and that is exactly what this customer is doing. He replaced the SAN with DRBD and now he can easily move one VMware instance to the other host. Possibly it is not that flexible and powerful as an ESX Server but also not so …