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Displaying posts with tag: slave (reset)

Prewarm your EBS backed EC2 MySQL slaves
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This is the story of cold blocks and mismatched instances and how they will cause you pain and cost you money until you understand why.

Most of the clients that we support run on the Amazon cloud using either RDS or running MySQL on plain EC2 instances using (Provisioned IOPS) PIOPS EBS for data storage.

As expected the common architecture is running a master with one or more slaves handling the read traffic.

A common problem is that after the slaves are provisioned (normally created from an EBS snapshot) they lag badly due to slow IO performance.

Unfortunately what tends to be lost in the “speed of provisioning new resources” fetish is some limitations in terms of data persistence layer (EBS).

If you are using EBS and you have created the EBS volume from snapshot or created a new volume you have to pre-warm the EBS volume

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Cloning a slave using Mysql Enterprise Backup on a GTID enabled server
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MySQL 5.6 introduced a new feature called GTID (Global Transaction IDentifier) support in Replication. For every transaction that is committed on to the server, a GTID of the format :

server_uuid:transaction_id is written into the master's binary log.

This offers the following advantages:

  • Very helpful to set up a slave and create a replication setup.

  • User need not worry about fetching the master's binlog filename and position in the “CHANGE MASTER TO” command which is used to synchronise the slave with the master.

  • Applying GTIDs on slaves ensures consistency – since GTIDs are unique, it cannot be applied more than once on the server.

For a gtid enabled server, the following properties

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MySQL requires an authoritative master to build slaves
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Read the original article at MySQL requires an authoritative master to build slaves

In MySQL database operations, you often need to rebuild slaves. They fail for a lot of different reasons, fall out of sync or crash. When this happens you may find you need to reclone and start fresh. This is normally done by finding your authoritative master database, and doing a hotbackup. Click through to the [...]

For more articles like these go to Sean Hull's Scalable Startups

Related posts:
  • Limitations of MySQL row-based replication
  • Why does MySQL replication
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    Automatically restarting MySQL slaves the easy way.
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    MySQL Replication is something that is used by many, many MySQL users, and here at Recorded Future we are no exception. In our case, the slaves are used for different purposes, and as we develop our system so much and so fast, so sometimes things happen which could have been avoided. Like something getting executed in the master that really should not end up in a slave at all, and which would cause all sorts of problems on the slave.

    Also, some things that work fine on the master can sometimes cause things to break on the slave, a typical such issue is a big operation on the master that when executed on the slave would cause a lock timeout. And you could argue that the lock timeout should be increased, but the question is how much, and frankly, do you really want those locks hanging around? And in some

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    Memory tuning fast paced ETL
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    Dear Kettle friends,

    on occasion we need to support environments where not only a lot of data needs to be processed but also in frequent batches.  For example, a new data file with hundreds of thousands of rows arrives in a folder every few seconds.

    In this setting we want to use clustering to use “commodity” computing resources in parallel.  In this blog post I’ll detail how the general architecture would look like and how to tune memory usage in this environment.

    Clustering was first created around the end of 2006.  Back then it looked like this.

    The master

    This is the most important part of our cluster.  It takes care of administrating network configuration and topology.  It also keeps track of the state of dynamically added slave servers.

    The master is started

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    Slavereadahead 1.3 available
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    Version 1.3 of Slave read-Ahead is available for download. If you don't know what this tool is about, it is a tool that runs in the background, reads the incoming replication log on a slave and converts INSERT, UPDATE and INSERT ... SELECT statements into SELECT statements and executes these before the statement in question is executed on the server, the idea being that this will "prewarm" the MySQL caches for this date, for example the rows that an UPDATE is affecting will already be in the cache when the UPDATE arrives on the slave. Because of the way replication data is read, this tool only works with MySQL5.5 and up.

    Version 1.3 introduces the auto-reconnect feature. This will reconnect to the MySQL server if the connection fails. To be sure that we restart, all existing connectings are released

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    Slave Readahead 1.2 available
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    Version 1.2 of Slave Readahead is now available for download here. If you don't know what this little project is about, it is used to pre-warm the MySQL Cache for the Replication thread on MySQL slaves.

    It is built to support MySQL 5.5 and up only, as it uses some new commands in MySQL (like the SHOW RELAYLOG EVENTS admin command). For more information regarding this little project, either read this blogpost or download the documentation for the project.

    /Karlsson
    MySQL replication for demanding users
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    I have been working with MySQL replication for quite a while. I have dealt with simple replication setups and I have experimented with complex ones. Five years ago I wrote an article about advanced MySQL replication, which was mostly a dream on what you could do with imagination and skill, but the matter from that article is still not even remotely ready for production. Yet, since that article, I have been approached by dozens of people who wanted to know how to make the multiple master dream become reality. To all of them, I had to say, "sorry, this is just a proof of concept.Come back in a few years, it may become possible". It still isn't.
    Despite its latest great technological advance, MySQL native replication is is very poor of topologies. What you can do with MySQL native
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    Setting up Master-Slave Replication with MySQL
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    Replication enables data from one MySQL server to be replicated on one or more other MySQL servers. Replication is mostly used as scale-out solution. In such a solution, all writes and updates take place on the master server, while reads take place on one or more slaves. This model is actually known as master-slave replication and this is the kind of replication that I will be setting up in this post.
    A first look at delayed replication in MySQL 5.6
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    If you like fresh features, you should not miss this one. MySQL 5.6.2 includes, among other improvements, the implementation of Time delayed replication, a feature that lets you tell the slave not to apply changes from the master immediately, but to wait N seconds.The feature is documented in WL#344. (There was a manual online as well together with the binaries for MySQL 5.6.0, but they were removed after a few days for a good reason. I am confident that both the manual and some binaries will eventually show up soon).
    Since as of today there are no binaries
      [Read more...]
    Showing entries 1 to 10 of 29 10 Older Entries

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