You listed a lot of things - but no solution - i am looking for master - master configuration. Any tools you have used ? Anything concrete you can offer?
thanks On Mon, Jun 11, 2012 at 11:39 AM, Shawn Green <shawn.l.gr...@oracle.com> wrote: > On 6/11/2012 10:36 AM, Ananda Kumar wrote: >> >> ... >> Master-master allows load balancing. >> > > Why do people keep replication rings as if they are the best possible > configuration? A master-slave relationship also permits load balancing and > is easier to maintain and recover in the event of a node failure. > > Any MySQL replication topology cannot, in a generic sense, allow load > balancing. Careful precautions must be maintained in your load balancer and > in your application code to avoid data collisions (adding or modifying the > same PK on the same table on two or more nodes at the same time). > > For continuous uptime, you do need redundancy. For the 'limited downtime' > scenario that the customer proposed, this includes geographical redundancy > as well as physical duplication and should also include sharding his data so > that the loss of one sharded set (due to extreme disaster or comms failure) > does not knock all of his users offline at the same time. > > "realtime" data is also a variable definition. For hydrologic monitoring > data 'realtime' could mean within the last 15 minutes. For some > applications (such as telecommunication) 'realtime' is measured in > microseconds. It may be that the customer's requirements can tolerate a > normal variance in duplication time provided by MySQL's native replication. > If not, then rewriting (notice I did not say "porting") their application to > use MySQL Cluster may be the way to meet their "realtime" requirements. > > Yes, master-master replication can be useful (in an active-passive setup) > for rapid failover and recovery if you take the appropriate precautions. It > is not recommended for the newest administrators because recovery can become > complicated. One should really understand basic, top-down master-slave > replication before attempting to create a replication ring. > > Active-Active (dual master) configuration is even more complicated and is > suited only for specific application purposes. This is definitely an > advanced technique and requires careful planning and engineering to perform > properly. > > Regards, > -- > Shawn Green > MySQL Principal Technical Support Engineer > Oracle USA, Inc. - Hardware and Software, Engineered to Work Together. > Office: Blountville, TN > > > > > -- > MySQL General Mailing List > For list archives: http://lists.mysql.com/mysql > To unsubscribe: http://lists.mysql.com/mysql > -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/mysql
