[DRBD-user] mysql on drdb or mysql replication

Lars Ellenberg Lars.Ellenberg at linbit.com
Sat Feb 11 13:15:51 CET 2006

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


/ 2006-02-10 11:22:14 -0600
\ Nate Reed:
> I must have lost track of the discussion.  :)  I didn't suggest running MySql 
> Cluster on a single node.  Clearly, one has to choose between 1) MySql 
> clustering on multiple nodes and 2) using DRBD active/passive with mysql 
> running on a single node.  Not both.

I think there are at least three options:

*) mysql cluster product
   read up on the mysql site on what requirements/implications this has
   for your generel setup...
   this is probably more suitable if you don't primarily need high availability,
   but also high performance

*) "standard" mysql replication
   this is not the mysql cluster product, but log-based, asynchronous
   replication of updates from one mysql node to possibly multiple ones.
   can also be daisychained, or used in other creative ways.

   good if you can distribute selects over many servers, even if some of
   the returned data is sometimes slightly out-of-date (the replication
   log has not yet been fully applied on the currently used server; that
   is what "asynchronous" implies).

   updates have to happen on the mysql-master only.
   (even though one could update on a slave, too, and achieve
   "interessting" effects ...)

   I remember that there have been issues replicating update queries
   that lead to mysql-errors. this may have been fixed.

   may improve availability (you need to script things to make one of the
   former replication targets the new replication master in case the
   current master fails) as well as performance (if you can distribute
   many selects on several servers)

*) mysql on drbd + heartbeat
   mysql is running only on one node (the currently active one) at a given time.
   due to drbd overhead (mainly network latency) in most cases a slight
   performance hit.
   but should improve availability :)

-- 
: Lars Ellenberg                                  Tel +43-1-8178292-0  :
: LINBIT Information Technologies GmbH            Fax +43-1-8178292-82 :
: Schoenbrunner Str. 244, A-1120 Vienna/Europe   http://www.linbit.com :
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