PlanetMysql.ru — информация о СУБД MySQL

[UPDATE 2011/01/11] : New poll added, vote for the best GUI client tool ! (And continue to vote for other polls)
And thanks again for your involvement. It’s time to vote again… 

First of all, I wish you a happy new year.
Many things happened last year, it was really exciting to be involved in the MySQL ecosystem.
I hope this enthusiasm will be increased this year, up to you !

To start the year, I propose the MySQL+ Community Awards 2011
It will only take 5 minutes to fill out these polls.
Answer with your heart first and then with your experience with some of these tools or services.

Polls will be closed January 31, so, vote now !
For “other” answers, please,  let me a comment with details.

Don’t hesitate to submit proposal for tools or services in the comments.
And, please, share these polls !

 

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Happy 2012 !
Cédric

This article is obviously not sponsored !
(MySQL is a trademark of Oracle Corporation and/or its affiliates)

Sources :

• Oracle products, tools and services : http://www.mysql.com
• SkySQL products, tools and services : http://www.skysql.com
• Percona products, tools and services : http://www.percona.com
• FromDual products, tools and services : http://www.fromdual.com
• PalominoDB products, tools and services : http://palominodb.com/
• Pythian products, tools and services : http://www.pythian.com/
• Blue Gecko products, tools and services : http://www.bluegecko.net/
• Zabbix : http://www.zabbix.com/
• MySQL Cacti templates : http://code.google.com/p/mysql-cacti-templates/
• Nagios : http://www.nagios.org/
• r1soft CDP for MySQL : http://www.r1soft.com/linux-cdp/cdp-enterprise-edition/mysql/ 
• mylvmbackup tool : http://www.lenzg.net/mylvmbackup/
• mydumper tool : http://www.mydumper.org/
• ZRM tools : http://www.zmanda.com
• Galera replication : http://codership.com/products/galera_replication
• Tungsten replicator : http://code.google.com/p/tungsten-replicator/
• DRBD : http://www.drbd.org/
• ShoonerSQL : http://www.schoonerinfotech.com/products/schoonersql
• ScaleBase : http://www.scalebase.com/
• common-schema : http://code.google.com/p/common-schema/
• innotop : http://code.google.com/p/innotop/
• MySQL Tuner : https://launchpad.net/mysqltuner/2.0/mysqltuner-2.1-rev17
• mycheckpoint : http://code.openark.org/forge/mycheckpoint
• MariaDB : http://mariadb.org/
• TokuDB : http://www.tokutek.com/
• InfiniDB : http://infinidb.org/
• Drizzle : https://launchpad.net/drizzle
• Amazon SimpleDB : http://aws.amazon.com/fr/simpledb//180-2635771-0721067/
• mongoDB : http://www.mongodb.org/
• Cassandra : http://cassandra.apache.org/
• CouchDB : http://couchdb.apache.org/
• Tokyo Cabinet : http://fallabs.com/
• Riak : http://basho.com/
• Hadoop : http://hadoop.apache.org/
• Tarantool : http://tarantool.org/
• memcached : http://memcached.org/
• MySQL Sandbox : http://mysqlsandbox.net/
• openark kit : http://code.openark.org/forge/openark-kit
• Redis : http://redis.io/
• Ganglia : http://ganglia.sourceforge.net/
• HandlerSocket : https://github.com/ahiguti/HandlerSocket-Plugin-for-MySQL

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One more DRBD tutorial, this time I will describe howto setup MySQL with DRBD (Distributed Replicated Block Device). Purpose This document describes how to to setup a failover system with MySQL and DRBD (Distributed Replicated Block Device). Introduction In this tutorial we will setup two Debian Linux nodes with a DRBD volume. MySQL will be [...]
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When I read on the internetz that Alex Davies was about the publish a Packt book on MySQL HA I pinged my contacts at Packt and suggested that I'd review the book .

I've ran into Alex at some UKUUG conferences before and he's got a solid background on MySQL Cluster and other HA alternatives so I was looking forward to reading the book.

Alex starts of with a couple of indepth chapters on MySQL Cluster, he does mention that it's not a fit for all problems, but I'd hoped he did it a bit more prominently ... an upfront chapter outlining the different approaches and when which approach is a match could have been better. The avid reader now might be 80 pages into MySQL cluster before he realizes it's not going to be a match for his problem.

I really loved the part where Alex correcly mentions that you should probably be using Puppet or so to manage the config files of your environment, rather than scp them around your different boxes ..

Alex then goes on to describe setting up MySQL replication and Multi Master replicataion with the different approaches one can take here, he gives some nice tips on using LVM to reduce the downtime of your MySQL when having to transfer the dataset of an already existing MySQL setup, good stuff.

He then goes on to describe MySQL with shared storage ... if you only mount your redundant sandisk once on your MySQL nodes my preference would probably be a Pacemaker stack rather than a RedHat Cluster based setup, but his setup seems to work too. Alex quickly touches on using GFS to have your data disk mounted simultaneously on both nodes (keep in mind with only 1 active MySQLd) and then goes on to describe a full DRBD based MySQL HA setup

The last chapter titled Performance tuning gives some very nice tips on both tuning your regular storae, as your
GFS setup but also the tuning parameters for MySQL Cluster

I was also really happy to see the Appendixes on the basic installation where he advocates the use of Cobbler , Kickstart and LVM ..

One of the better books I read the past couple of years .. certainly the best book from Packt so far , I hope there is more quality stuff coming from that direction !

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A couple of weeks ago one of my colleagues and I worked on a data corruption case that reminded me that sometimes people make unsafe assumptions without knowing it. This one involved SAN snapshotting that was unsafe.

In a nutshell, the client used SAN block-level replication to maintain a standby/failover MySQL system, and there was a failover that didn’t work; both the primary and fallback machine had identically corrupted data files. After running fsck on the replica, the InnoDB data files were entirely deleted.

When we arrived on the scene, there was a data directory with an 800+ GB data file, which we determined had been restored from a SAN snapshot. Accessing this file caused a number of errors, including warnings about accessing data outside of the partition boundaries. We were eventually able to coax the filesystem into truncating the data file back to a size that didn’t contain invalid pointers and could be read without errors on the filesystem level. From InnoDB’s point of view, though, it was still completely corrupted. The “InnoDB file” contained blocks of data that were obviously from other files, such as Python exception logs. The SAN snapshot was useless for practical purposes. (The client decided not to try to extract the data from the corrupted file, which we have specialized tools for doing. It’s an intensive process that costs a little money.)

The problem was that the filesystem was ext2, with no journaling and no consistency guarantees. A snapshot on the SAN is just the same as cutting the power to the machine — the block device is in an inconsistent state. A filesystem that can survive that has to ensure that it writes the data to the block device such that it can bring into a consistent state later. The techniques for doing this include things like ordered writes and meta-data journaling. But ext2 does not know how to do that. The data that’s seen by the SAN is some jumble of blocks that represents the most efficient way to transfer the changed blocks over the interconnect, without regard to logical consistency on the filesystem level.

Two things can help avoid such a disaster: 1) get qualified advice and 2) don’t trust the advice; backups and disaster recovery plans must be tested periodically.

This case illustrates an important point that I repeat often. The danger of using a replica as a backup is that data loss on the primary can affect the replica, too. This is true no matter what type of replication is being used. In this case it’s block-level SAN replication. DRBD would behave just the same way. At a higher level, MySQL replication has the same weakness. If you rely on a MySQL slave for a “backup,” you’ll be out of luck when someone accidentally runs DROP TABLE on your master. That statement will promptly replicate over and drop the table off your “backup.”

I still see people using a replica as a backup, and I know it’s just a matter of time before they lose data. In my experience, the types of errors that will propagate through replication are much more common than those that’ll be isolated to just one machine, such as hardware failures.

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This is a Request for Input. Dual MySQL masters with MMM in a single datacentre are in common use, and other setups like DRBD and of course VM/SAN based failover solutions are conceptually straightforward also. Thus, achieving various forms of resilience within a single data-centre is doable and not costly.

Doing the same across multiple (let’s for simplicity sake limit it to two) datacentres is another matter. MySQL replication works well across longer links, and it can use MySQL’s in-built SSL or tools like stunnel. Of course it needs to be kept an eye on, as usual, but since it’s asynchronous the latency between the datacentres is not a big issue (apart from the fact that the second server gets up-to-date a little bit later).

But as those who have tried will know, having a client (application server) connection to a MySQL instance in a remote data-centre is a whole other matter, latency becomes a big issue and is generally very noticeable on the front-end. One solution for that is to have application servers only connect to their “local” MySQL server.

So the question to you is, do you now have (or have you had in the past) a setup with MySQL masters in different datacentres, what did that setup look like (which additional tools and infra did you use for it), and what were your experiences (good and bad, solutions to issues, etc). I’m trying to gather additional expertise that might already be about, which can help us all. Please add your input! thanks

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I recently presented a webcast hosted by O’Reilly and Webex.  In it I take you on a step-by-step installation of DRBD and MySQL.  I start by using Sun’s Virtualbox to create to virtual machines running CentOS.  I then explain how to configure them with virtual external drives to use for DRBD.  I next configure the network interfaces to support routed packets into and out of the boxes.  Then I install various packages with yum, configure drbd and finally install MySQL as the last step.  You can follow along at the command line and do it yourself on a Windows, Mac or Linux box.

PlanetMySQL Voting: Vote UP / Vote DOWN

Funny how different experiences lead to different evaluations of tools. The MySQL HA solutions the MySQL Performanceblog list, are almost listed in the complete opposited order of what my impressions are.

Ok agreed, I should probably not put my MySQL NDB experiences from 2-3 years ago with multiple Query of deaths and more problems than you into account anymore , but back then went in the list Less stable than a single node. I've had NDB POC setups going down for much more than 05:16 minutes
Ndb comes with a lot of restrictions, there are

As for MySQL on DRBD, I've said this before , I love DRBD, but having to wait for a long InnoDB recovery after a failover just kills your uptime ,
I remember being called by a customer during Fred last holiday who was waiting over 20 minutes for recovery , twice, so putting the DRBD/San setup second would not be my preference. But agreed .. it's only listed at 99.9% meaning almost 9 hours of downtime per year are allowed.

On the other hand we've seen database uptime of MySQL MultiMaster setups with Heartbeat reaching better figures than 99.99% Heck I've seen single nodes achieve better than 99.99% :)

So what does this teach us ... there is no golden rule for HA, lots of situations are different, it's the preferences of the customer, the size of the database, the kind of application , and much
more .. you always need to think and evaluate the environment ...

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I’m happy to extend a warm welcome to two new members of the Percona team.

First is Yves Trudeau, about whom I can say many things:

• One of the top MySQL Cluster (NDB Cluster) experts in the world.
• An expert on all things High Availability, including DRBD and Heartbeat.
• Many years of experience with Huge Data.
• Half of the Waffle Grid team.
• A really nice person!

Yves joins us after a tenure of several years as a senior consultant at Sun/MySQL. Together with Matt Yonkovit, he plans to work on WaffleGrid (but as a new project under a new name, to be determined), and integration with XtraDB. Yves lives in Quebec with his family.

Next is Fernando Ipar. Fernando is our first dedicated Shift Support Captain^[1]. Fernando specializes in MySQL, GNU/Linux, systems administration, and high availability. Fernando has been involved in computer programming since he was 11, and in Open Source since 2001. He loves shade-grown coffee, music, and natural history. He lives in Uruguay with his wife and family. Fernando brightens our IRC channel with his helpful and cheerful presence!

Welcome, Yves and Fernando!

[1] Shift Support Captain is kind of a dispatcher for 24-hour service. We have been doing 24×7 service through an on-call phone number for years, but a few months ago we started literally manning the desk 24×7 — something that we have grown large enough to both need and justify, at our current size of around 30 people. Our customers can now use email, Skype, AOL messenger, or Google Chat (as well as the phone number) to get immediate attention, 24×7, from a technically savvy person.

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