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Read the original article at Make MySQL clustering work for you
We’ve told you all about MySQL mult-master replication’s limitations. If you write to two masters it is bound to fail for myriad reasons. Now what? Do what the pros do that’s what. A. Don’t write to both masters Using multi-master replication works great as long as you do so in active-passive mode. Never write to [...]
For more articles like these go to Sean Hull's Scalable StartupsRelated posts:
In the first part of this article we examined the types of conflicts and their causes. In this part, we will analyse some of the methods available to deal with conflicts.
Applicability: synchronous clusters with 2pc
We've covered this topic in the previous article, but it's worth repeating. If you use a synchronous cluster, you don't have conflicts. For example, MySQL Cluster ensures consistent data with updates coming from different nodes. However, MySQL Cluster is not a replacement for a MySQL server, and it has severe limitations.
Applicability: synchronous clusters without 2pc (Galera)
Conflicting transactions proceed on different[Read more...]
The Percona Live MySQL Conference and Expo 2013 is almost 1 month away. It's time to start planning, set the expectations, and decide what to attend. This post will give a roundup of some of the sessions that I recommend attending and I look forward to.
After much talk and disbelief, here they come! Oracle (http://www.mysql.com) engineers will participate to the Percona Live conference. This is wonderful! Their participation was requested by the organizers, by the attendees, and by community advocates, who all told the Oracle management how important it is to be in this conference. Finally, they have[Read more...]
In my job, I do a lot of testing. And no matter how much organized we try to be, we end up with fewer machines than we would need to run all the tests that we want.
For some tasks, we can run MySQL Sandbox, and get the job done. But sometimes we need to make sure that applications and systems work well across the network, and we need to install and run systems on separate servers.
However, when you test replication systems, and every cluster takes three or four servers, you run our of available hosts very quickly. So you decide to use the clusters that are dedicated to automated testing to also run your own manual tests. Soon you realize that the tests that you are running manually are clashing with the automated ones, or with the ones that your colleagues are running.
A simple solution[Read more...]
Tungsten Replicator version 2.0.6 was released today.
You can get both the binaries and the source code at the project's downloads page.
This release contains many bug fixes, and various improvements. All of them are listed in the Release Notes. The most interesting ones are the improvement in multi-master topologies. Using this release with star topologies you will get less traffic than before, because we have reduced some duplication of transaction history logs that were sent between servers.
And speaking of multi-master topologies, this release includes the cookbook recipes mentioned in this blog[Read more...]
I have been asked many times to provide an easy way of deploying fan-in and star schema replication schemas. So far, I have been delayed by more pressing duties.
Now the time has come. Since we are about to release a new version of Tungsten Replicator, I made the effort of putting together the steps for an easy deployment.
The package (with downloads and svn code available at Tungsten-Replicator Toolbox) includes some juicy goodies. There are recipes to install.
Fig 1. Master/Slave topology[Read more...]
About a month ago I needed to compare tens of thousands of tables in hundreds of databases between a few different servers. The obvious choice was, mk-table-checksum! The only problem was, that the tool needs to know the minimum and maximum value of the column by which each table is to be subdivided into chunks and checksummed. This select min(col), max(col) from table locks all write operations on the table and on a big table it meant downtime.
Looking at the source it was clear we could make mk-table-checksum run the select min(col), max(col) from table on the read-only slave and use the values to checksum the master.
It was subtle code changes in function:
my $cxn_string_dc = “DBI:mysql:;host=slavehost;port=3306;mysql_read_default_group=client”;
my $user = ‘user’;
SHOW SLAVE STATUS—the twist is that the implementation is entirely done in the server, using pure SQL.
If you're familiar with[Read more...]
This Thursday (October 22nd, 13:00 UTC), Walter Heck (of Open Query) will present Dual Master Setups With MMM. MMM (Multi-Master Replication Manager for MySQL) is a set of flexible scripts to perform monitoring/failover and management of MySQL master-master replication configurations (with only one node writable at any time). Session slides (PDF).
The toolset also has the ability to read balance standard master/slave configurations with any number of slaves, so you can use it to move virtual IP addresses around a group of servers depending on whether they are behind in replication. For more
information, see mysql-mmm.org.
For MySQL University sessions you point your[Read more...]
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