[DRBD-user] MySQL solution

paddy paddy at panici.net
Mon Nov 21 22:43:56 CET 2005

Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.


On Mon, Nov 21, 2005 at 05:59:20PM -0300, André Moreira wrote:
> Hi,
>   I'm a newbie on DRBD.

please don't get the impression that I'm not ...

> I'd like to know if someone has a solution for
> MySQL cluster using DRBD. 

I'm using MySQL on ext3 on drbd, but only lightly.

I understood from the list that others have much more experience
with MySQL over drbd.

> And, the answers to questions like what
> happens if the files used by MySQL remain locked when the passive take
> action? How to avoid it? 

two scenarios come to mind:

controlled standby:

  you use something like heartbeat to take it down gently

  I have an (mildly) entertaining story about how to shoot yourself in 
  the foot with heartbeat by getting the details wrong :)

active catches fire (or whatever):

  passive node does whatever a system would do after a crash ...
  potentially fsck, MySQL's equivalent of fsck ...

  I vaguely recall mention of whether journalled filesystems 
  should be good to go (or not) without an fsck ...

  also does it depend on which drbd protocol you're using?

> Is it possible to load balance?

I don't know of a way using such a setup, but I'm all ears.

There are other solutions that do forms of load-balancing, such as 
MySQL replication or MySQL cluster.  

I guess it's horses for courses.

Regards,
Paddy
-- 
Perl 6 will give you the big knob. -- Larry Wall



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