很久之前看过这个帖子,当时没有细究,这几天看了下mysql相关的internal 突然想起这个问题,跟三四个朋友讨论了下 想把这个问题展开讲一讲。
源帖子内容见：https://community.oracle.com/thread/1087650?start=0&tstart=0
这个帖子的内容为一个老外问oracle如何避免partial write的,也就是大家所说的半个IO问题,IO
在写到一半的时候发生断裂,（瞬间断线,瞬间crash瞬间存储或者机器故障等）
虽然这个情况极少发生,但是在非常规恢复的时候也是经常遇到的,例如某个block内部出现不一致,也就是我们所谓的逻辑坏块。
我仔细的又过了一遍帖子,发现下面的几个回答完全不准确,或者有点张冠李戴的意思。
首先我们看看什么是mysql 的double write:
—–引自 …
[Read more]Percona is glad to announce the new release of Percona XtraDB Cluster 5.6 on September 1st 2014. Binaries are available from downloads area or from our software repositories.
Based on Percona Server 5.6.20-68.0 including all the bug fixes in it, Galera Replicator 3.7, and on …
[Read more]
Recently we faced an issue when Nagios reported significant
amount of “Locked” queries.
To investigate and debug the issue we needed to get more insight
about the state of MySQL and the OS at the time the locks
occurred.
This is how we got the much needed information:
wget http://bit.ly/1ltoZtk -O pt-stalk
chmod +x pt-stalk
mkdir -p /tmp/pt-stalk
sudo pt-stalk --daemonize --notify-by-email <EMAIL> --log
/tmp/pt-stalk/pt-stalk.log --user root --dest /tmp/pt-stalk
--function processlist --variable State --match Locked
--threshold 20 --cycles=10 --sleep=15 --run-time=15
In this case we are running pt-stalk utility in background and trying to catch the case when there are 20+ Locked queries in processlist. When a match occurs, pt-stalk will collect a lot of OS and MySQL info and notify us by email.
Join 27,000 others and follow Sean Hull on twitter @hullsean. I was shocked to find this article on ReadWrite: The Truth About DevOps: IT Isn’t Dead; It’s not even Dying. Wait a second, do people really think this? Truth is I have heard whispers of this before. I was at a meetup recently where the […]
It has been just over 2 weeks since the last libAttachSQL
version was released. I had a great vacation in the middle
which for once meant that I didn't do any work for the week I was
away :)
For those who don't know about it, libAttachSQL is a lightweight,
non-blocking C connector for MySQL servers. It is Apache
2.0 licensed so plays well with both Open Source and Commercially
licensed applications. I have been developing it for 2
months now as part of my work for HP's Advanced Technology Group.
It is hosted on GitHub and uses many freely available
tools (such as Travis CI) to host and test various
parts of the project.
Once again I thank everyone for the feedback I have received. …
The MySQL for Database Administrators training course is one of the most popular courses at Oracle. This is not surprising since it provides a comprehensive range of administration skills to those using the world's most popular open source database.
You can travel to an education center to take this 5-day instructor-led course, and as shown in the table below, events are currently scheduled for delivery in 8 languages (Arabic, Brazilian Portuguese, English, French, Hebrew, Italian, Spanish, Turkish).
If you want to take this training from your own desk, you have two options:
Galera replication for MySQL brings not only the new, great features to our ecosystem, but also introduces completely new maintenance techniques. Are you concerned about adding such new complexity to your MySQL environment? Perhaps that concern is unnecessarily.
I am going to present here some simple tips that hopefully will let fresh Galera users prevent headaches when there is the need to recover part or a whole cluster in certain situations. I used Percona XtraDB Cluster (project based on Percona Server and Galera library + MySQL extensions from Codership) to prepare this post, but most if not all of the scenarios should also apply to any solution based on MySQL+Galera tandem you actually chose, whether these are binaries from Codership, MariaDB Galera Cluster or …
[Read more]September 1, 2014 By Severalnines
According to Forrester, a DBA in a large enterprise manages between 8 and 275 databases, with the industry average being 40 databases to a DBA. Larger databases usually require extra effort around tuning, backup, recovery and upgrade. Cloud, as well as automation and management tools can help improve the number of databases managed by one DBA.
With that background, we were pretty excited to introduce support for management of single-instance MySQL and MariaDB databases in ClusterControl 1.2.6. The majority, if not all of the cluster users out there, use single-instance or master-slave replicated setups along their mission-critical …
[Read more]
To get more familiar with docker and to create a test setup for
MySQL Cluster I created docker images for the various components
of MySQL Cluster (a.k.a. NDB Cluster)
At first I created a Fedora 20 container and ran all components
in one container. That worked and is quite easy to setup. But
that's not how one is supposed to use docker.
So I created Dockerfile's for all components and one base
image.
The base image:
The management node (ndb_mgmd) image:
After mysql installation, To make mysql server production ready we have to tune default mysql variables considering the hardware, production load, performance, durability etc.
But What about the optimizing Linux OS settings with mysql ?
Here it is, i encountered an issue once when i was checking TOP output for mysqld process and found that the mysqld memory continuously increasing. Also there was one more thing that it was using swap memory even if there was enough RAM memory available. we have monitored for a week and this was causing an issue like slow query processing, performance and slowness on DB server.
To solve this problem we have to set correct swappiness
…
[Read more]
