MySQL and DRBD, Often say NO :)
Florian is replying to James on the subject of using DRBD for MySQL HA. A discussion started earlier by Eric Florian is refuting most of the arguments that James has against using MySQL and DRBD together.
I`m also saying NO to MySQL and DRBD in most of the cases.. but not for any of the reasons James mentions.
I must say upfront I love DRBD and I have been using it in production for a long time but not for MySQL HA.
The problem with using MySQL on DRBD is the same problem you have when killing the power on a standalone MySQL machine and rebooting that machine.
DRBD saves you the time of powering up your machine and OS. But MySQL still needs to be started again on the standby machine. (In limited cases you might have a lengthy startup process due to eg. Innodb consitency checks) But for lots of organisations this (even limited) downtime is not acceptable.
Both MySQL Cluster and MultiMaster replication give you constant access to your data on more nodes .
For lots of shops, those not needing to scale, those that can live with a limited downtime, DRBD and MySQL is a good match,
But if you want to achieve real high availability as compared to less downtime. or if you are looking to scale your MySQL and want to benefit from HA while you are at it , then MultiMaster is probably the preferred alternative as opposed to DRBD.
In the meanwhile I`ll be happy serving other data from my DRBD volumes ;)