[DRBD-user] Drbd mysql

Stefan Seifert nine at detonation.org
Thu Aug 23 08:55:24 CEST 2007


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alex at crackpot.org wrote:
> Quoting Lars Ellenberg <lars.ellenberg at linbit.com>:
> 
>> so replicating it using drbd and a cluster file system,
>> and then simultaneously accessing it with a second mysql instance
>> on a second box
>> can not magically make it work.
>>
>> to have more than one application instance access the same data source,
>> they have to coordinate access,
>> whether they run on a single host, or on two different hosts.
>> not only writes (that should be obvious),
>> but also reads, to avoid cache coherency issues.
> 
> You can do this if you configure MySQL to use external locking.

Why not simply use MySQL clustering, if clustering is, what's needed?
http://dev.mysql.com/doc/refman/5.0/en/mysql-cluster.html


Of course this only makes sense, if the rest of the application can be
clustered, too. If not, replication is much easier and works great.

Stefan
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