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Previous 30 Newer Entries Showing entries 61 to 90 of 102 Next 12 Older Entries

Displaying posts with tag: centos (reset)

Installing PowerDNS (With MySQL Backend) And Poweradmin On CentOS 5.2
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Installing PowerDNS (With MySQL Backend) And Poweradmin On CentOS 5.2

This article shows how you can install the PowerDNS nameserver (with MySQL backend) and the Poweradmin control panel for PowerDNS on a CentOS 5.2 system. PowerDNS is a high-performance, authoritative-only nameserver - in the setup described here it will read the DNS records from a MySQL database (similar to MyDNS), although other backends such as PostgreSQL are supported as well. Poweradmin is a web-based control panel for PowerDNS.

How popular is an Open Source project ?
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There is a really easy way to figure out ...

Look at the size of of the devrooms , if at all , a project gets at Fosdem
It's really interresting to see the Embedded room move to a 500 seat room which it really needed when the first openMoko talk was held there in a previous edition.

The FDO , Drupal, Mozilla, Centos/Fedora and Suse rooms stay in similar size rooms as last year.. But it seems lik the BSD and PostgreSQL room which was pretty crowded moved to a bigger location.

The Ruby room also seems to move to a bigger room. Fosdem has a couple of new rooms too it seems this freed up room for new groups such as the MySQL Crowd

Obviously these sizes aren't a real match to the size of a community, as the new rooms might need (and probably will need) a


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ZRM 2.1: Backing Up MySQL Partitioned Tables
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ZRM 2.1: Backing Up MySQL Partitioned Tables

MySQL 5.1 is generally available for production use. One of the key features of MySQL 5.1 is partitioning. This how to shows how to install and configure Zmanda Recovery Manager for MySQL (ZRM) 2.1 to perform backup and recovery of MySQL partitioned tables.

Server Monitoring With munin And monit On CentOS 5.2
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Server Monitoring With munin And monit On CentOS 5.2

In this article I will describe how you can monitor your CentOS 5.2 server with munin and monit. munin produces nifty little graphics about nearly every aspect of your server (load average, memory usage, CPU usage, MySQL throughput, eth0 traffic, etc.) without much configuration, whereas monit checks the availability of services like Apache, MySQL, Postfix and takes the appropriate action such as a restart if it finds a service is not behaving as expected. The combination of the two gives you full monitoring: graphics that lets you recognize current or upcoming problems (like "We need a bigger server soon, our load average is increasing rapidly."), and a watchdog that ensures the availability of the monitored services.

451 CAOS Links 2008.11.21
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Sun updates MySQL Enterprise. The Microsoft/Novell deal is two years old. Nuxeo and Boxee get funding. Red Hat’s CEO on open source in a downturn. Steve Ballmer as a glove puppet. And more.

Press releases
Sun Enhances MySQL Enterprise With New Query Analyzer Tool to Boost Database Application Performance Sun Microsystems

Microsoft and Novell Mark Two Years of Interoperability Progress Microsoft

Nuxeo secures 2 million Euros and strengthens its board of directors and corporate governance Nuxeo


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Let the customer choose where to buy lunch from !
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Matt Asay is pushing his favorite Open Source model again. The model where the majority of developers of a project work for a company and that company is creating a business around the project. There's nothing wrong with that model, but he seems to forget the other models time over time :)

Matt is absolutely right with 2 of the 3 things he wants you to consider.
A SI in the middle of a $50 million dollar project involving Alfresco not talking to Alfresco is just wrong. An SI not offering a support contract is also just wrong. But an SI forcing his customer to buy the commercially supported version from a vendor ? Where's the customer choice ?

The customer should have the option to choose for a commercially supported version or the free version. And preferably that should be an educated option.


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sshfs: How do you install sshfs and fuse? [CentOS/Linux/Redhat]
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One may wonder what is sshfs and why would you want it?  Well simply put, sshfs allows you to mount another server’s filesystem into a folder on your local system which in the background is doing ssh commands and transfers.  As a mounted folder, you are able to move about and copy files back and forth as everything was on local server.  As you can see this makes it very easy for you to work with files on multiple servers.

Note:  you only have to do the following installations on the server where you are doing the mounts on.

Let us download and install the filesystem framework which is a requirement for sshfs called fuse.

wget http://voxel.dl.sourceforge.net/sourceforge/fuse/fuse-2.7.4.tar.gz
tar zxpfv fuse-*.gz
cd fuse*
./configure

If you get the following error, you will either have to point to the




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This should *never* happen!
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While playing around with the great MySQL Activity Reporter , I ran into the following error.

[client 192.168.254.72] PHP Fatal error: strftime() [function.strftime]: Timezone database is corrupt - this should *never* happen! in /var/lib/mysqlard/mysqlar.php on line 62

Now the error is clear .. the Timezone database is corrupt and I`m the one to blame for .. this was on a pretty stripped down Centos that lives in UTC. So there wasn't a real Timezone database.

Obviously a quick apt-get install tzdata solved the problem, but once again the lesson is.. don't strip too much .. you'll eventually endup needing those 3 Kb of free space you gained anyhow.

This should *never* happen!
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While playing around with the great MySQL Activity Reporter , I ran into the following error.

[client 192.168.254.72] PHP Fatal error: strftime() [function.strftime]: Timezone database is corrupt - this should *never* happen! in /var/lib/mysqlard/mysqlar.php on line 62

Now the error is clear .. the Timezone database is corrupt and I`m the one to blame for .. this was on a pretty stripped down Centos that lives in UTC. So there wasn't a real Timezone database.

Obviously a quick apt-get install tzdata solved the problem, but once again the lesson is.. don't strip too much .. you'll eventually endup needing those 3 Kb of free space you gained anyhow.

Linux: How do you find out what your server’s outgoing ip is?
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There are many times when I needed to find out my outgoing (or external) IP for the servers which are behind load balancers or firewalls.  I used to just login to another external server from the server in question and find out by looking at “who” what my external ip is.  Even though it works and I am so used to it, today I decided to figure out a more graceful way of finding my outgoing ip.  As most of us already know, whatismyip.com is the quickest way to find out your outgoing ip from the browser.  So I decided to use the same way on the servers.  So I issued a wget:

wget http://www.whatismyip.org

Well that does the trick.  But being lazy as I am, I did not want to have to cat the output file to find out the ip (plus there is no point of creating extra files and

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Building mysql-proxy-0.6.0 on CentOS-5.2
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I recently needed to configure mysql failover on some of our test machines. Thanks to Sheeri’s helpful blog entry which provides a simple failover lua script, configuring failover is a simple matter. However, the machines are running centos-5.2 and centos doesn’t provide an rpm for mysql-proxy. This blog entry describes how to build your own.

The latest mysql-proxy (0.6.1) is apparently not backward-compatible with 0.6.0 and earlier. It incorrectly handles the case when one of the backend machines is down. Instead of just marking it as down, it errors out completely. This makes it rather difficult to use it for failover scenarios. People have complained about this for a while. Bugs

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Quick tip: how do you rename all files so spaces are converted to underscores?
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My friend today asked me how to convert all spaces in filenames under a specified directory to underscores. Also, at the same time lowercase all of the filenames. Here is a quick script to do what is needed. Let us start with creating some test data in a temp directory:

mkdir temp
cd temp
touch Foo FooO "Foo Bar" "FOO BAaR"
\ls | while read -r FILENAME
do
mv -v "$FILENAME" `echo $FILENAME| tr ' ' '_'| tr '[A-Z]' '[a-z]'`
done

Note:  I intentionally have slash in front of ls (\ls).  \ls means that we want to make sure there is no ls alias overwriting our command. This is needed if your system has alias setup to display ls in a different way instead of default listing.  mv -v shows us the filenames being renamed as your script goes through the whole dir.  Your output should be like:

`Foo' -> `foo'







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Apache/http monitoring: monitor http traffic in realtime using httptop
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Server monitoring is a big part of running a solid web site.  As an admin, you must know what is going on your server.  One of the tools most Linux/Unix admins are used to is called “top”.  “top” by itself is a very powerful tool.  Here is a quick guide on how to read output from top:  introduction to load averages under top.  It just makes sense that somebody went and created httptop to monitor http traffic.

Install perl modules:

install Term::ReadKey
install File::Tail
install Time::HiRes

Now copy paste the script below and save it in a location and set +x attribute on it so you



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MySQL: How do you enable sphinxse (Sphinx Storage Engine) in your mysql installation?
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As you may know mysql fulltext search is not highly scalable.  One of the options to get around this scalability limitation, which I prefer, is to use Sphinx.  You can use Sphinx with out having to alter your mysql installation.  But, if you would like to use from within mysql and not have to worry about how to pass data between Sphinx and MySQL, you can enable sphinxse (sphinx storage engine).  It is not included with mysql by default so you will have to compile it yourself.

Here are the instructions on how to get sphinxse compiled with your mysql installation on CentOS x64.  I am sure same instructions will work for other flavors but I have not tested it.  I will be compiling the most current version of sphinx (0.9.8) with most current stable version of mysql (5.0.51b) at the time of the writing. 

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Spacewalk, and what we can learn about naming
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Red Hat releases Spacewalk. It is described as: “the upstream community project from which the Red Hat Network Satellite product is derived“. Congratulations to all whom have worked on it, especially my friends who tired endlessly over it in the past.

Red Hat, is sticking true to its promise, of open sourcing everything they make. Best of all, they recognise Fedora (they always did, since say, Fedora Core 2 or 3), CentOS (a direct “competitor”/rebuild of RHEL), and Scientific Linux (I know of a certain university’s sysadmin who will be blessing Spacewalk, as her life will now be a lot easier).

There have been a few blogs about it… Matt Asay asks about a community (Red Hat traditionally

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Installing MySQL Proxy On CentOS 5 (FINAL) x86_64
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Installing MySQL Proxy On CentOS 5 (FINAL) x86_64

This tutorial explains how you can install MySQL Proxy on a CentOS 5 (x86_64) system. MySQL Proxy is a simple program that sits between your client and MySQL server(s) that can monitor, analyze or transform their communication. Its flexibility allows for unlimited uses; common ones include: load balancing; failover; query analysis; query filtering and modification; and many more.

Installing MySQL Proxy On CentOS 5 (FINAL) x86_64
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Installing MySQL Proxy On CentOS 5 (FINAL) x86_64

This tutorial explains how you can install MySQL Proxy on a CentOS 5 (x86_64) system. MySQL Proxy is a simple program that sits between your client and MySQL server(s) that can monitor, analyze or transform their communication. Its flexibility allows for unlimited uses; common ones include: load balancing; failover; query analysis; query filtering and modification; and many more.

Linux: yum options you may not know exist.
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Most of the users who work with distributions such as: centos, fedora, redhat, etc use yum as a package update/installer. Most of them know how to do “yum update [packagename]” (to update all or [certain packages]) or they do “yum install packagename” to install certain package(s). But yum can do so much more. Here are some options you may find useful:

Following command will search for the string you specified. Generally this will give you all of the packages which has specified string in title or description. Most of the time you will have to look through a lot of output to find what you are looking for.

yum search string

Probably one of the most important options for yum is provides/whatprovides. If you know what command you need, you can find out what package you have to install in order to have that command available to

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Quick 'n' Easy LAMP Server For CentOS/RHEL
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Quick 'n' Easy LAMP Server For CentOS/RHEL

This tutorial shows a quick way of installing a LAMP server (Linux + Apache + MySQL + PHP/Perl together commonly known as LAMP Server.) on CentOS and RHEL server systems.

Maatkit in RHEL and CentOS
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Update: Karanbir says “Just one thing to keep in mind is that we dont want too many people using it from the Testing repository - we only need enough feedback to move it from testing to stable ( and to be honest, there are already 8 people who have said yes it works - so move to stable should happen within the next 24 - 48 hrs ). Once the package is in stable, users on CentOS4 and 5 wont need to do anything more than just ‘yum install maatkit’ and it will install for them.”

At least one person (Karanbir Singh) is working to get Maatkit into the CentOS repositories, and I believe there might be movement towards RHEL also. From an email to the Maatkit discussion list a little while ago,

I am in

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MySQL: How do I dump each record from a table to a separate files in csv format?
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I honestly do not know why somebody would want to export each record from a table in to its’ own files in a csv format. I am sure people have their own reasons. But since I got request from couple people, I figure I would post a solution here. Same script can be used to dump the whole table in to one csv file as well, with little tweaking. I will start with creating database with a table. I then insert three rows with test data into the table just to show three separate files creation.

mysql> CREATE DATABASE testdump;
mysql> USE testdump
mysql> CREATE TABLE `testtable` (
`id` TINYINT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY ,
`testfield` VARCHAR( 15 ) NOT NULL ,
`testfield2` VARCHAR( 15 ) NOT NULL
) ENGINE = innodb COMMENT = 'test table for dumping each row to file';
mysql> INSERT INTO `testtable` values






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Linux: How do you rename a user account in linux?
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In Linux, there is no command which will rename a user account. If you make a mistake creating a user account, user changes their name or if user does not like his user name, there is no real easy way of going and making the change. Only thing I know you can do is to go through some files and rename user manually. Let us say that we have a user who is named joe and we want to rename him to john.

Note: you must be logged in as root to do following.

vi /etc/passwd
find joe and change it to john, save/exit

vi /etc/group
find joe and change it to john, save/exit

vi /etc/shadow
find joe and change it to john. This file is read only and you have to force overwrite it. In vi it is :w! once saved, quit.

cd /home
mv joe john

And that should do the trick.

[Edited] Right after I posted this post, I was





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MySQL: How do you use symlinks with MySQL tables?
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Creating table symlinks in MySQL is very easy and it is probably one of the features a lot of MySQL users overlook or never think about. You may ask, why would I want to use symlinks? Some of the reasons you would want symlinks is if you are running low on disk space on the partition where your data generally is and/or you want to move one (or more) table(s) on to a different disk/partition for performance reasons.

One of the things worth mentioning is that MySQL documentation states: “Symlinks are fully supported only for MyISAM tables. For files used by tables for other storage engines, you may get strange problems if you try to use symbolic links.” Keeping that in mind, if you have a innodb table and would like to create symlinks for, you should change the engine type to myisam before symlinking. Although, I have heard and personally used symlinks for innodb

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Linux: How do you display specific information at login prompt in Linux on the console?
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Buddy of mine asked me a question over chat today: “how do I show my machines’ IP at login prompt with out logging in?” He is referring to his Virtual Machine in this case. He does not want to have to log in to the server to see what ip it has (since its on dhcp) for him to ssh in or hit it from the browser. I could have answered him with a simple how to but what is the fun in that? So I decided to give some background on how login prompts are done and show what can be done.

When Linux server boots up, it calls a program called mingetty. This program creates that infamous login prompt as show in a screenshot:

You can see how server calls the mingetty program by looking at /etc/inittab. You will see a block like below:

# Run

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pre-compiled binaries in your PATH
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I prefer to install mySQL using the pre-compiled binaries. Depending on the environment, these usually go in either /opt or /usr/local. When you choose this type of install, chances are you are going to need to ensure that you somehow configure your system so that the mysql binaries end up in your PATH. If you are [...]
MySQL: Solution for ERROR 1442 (HY000): Can’t update table ‘t1′ in stored function/trigger because it is already used by statement which invoked this stored function/trigger.
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Here is a sample table you can create to test following problem/solution on: CREATE TABLE `t1` ( `a` char(1) default NULL, `b` smallint(6) default NULL ); insert into t1 values ('y','1'); I have a table t1 which has column a and b, I want column a to be updated to ‘n’ when column b = 0. Here is the first version [...]
Virtual Hosting Howto With Virtualmin On CentOS 5.1
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Virtual Hosting Howto With Virtualmin On CentOS 5.1

This tutorial shows how to set up a CentOS 5.x server to offer all services needed by virtual web hosters. These include web hosting, smtp server with (SMTP-AUTH and TLS, SPF, DKIM, Domainkeys), DNS, FTP, MySQL, POP3/IMAP, Firewall, Webalizer for stats.

Virtual Hosting Howto With Virtualmin On CentOS 5.1
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Virtual Hosting Howto With Virtualmin On CentOS 5.1

This tutorial shows how to set up a CentOS 5.x server to offer all services needed by virtual web hosters. These include web hosting, smtp server with (SMTP-AUTH and TLS, SPF, DKIM, Domainkeys), DNS, FTP, MySQL, POP3/IMAP, Firewall, Webalizer for stats.

MySQL: How do you set up master-master replication in MySQL? (CentOS, RHEL, Fedora)
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Setting up master-master replication in MySQL is very similar to how we set up master/slave replication. You can read up about how to setup master/slave replication in my previous post: How to set up master/slave replication in MySQL. There is obviously pros and cons about using master/master replication. But this is not [...]   [Read more...]
Fosdem 2008
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This February I`ll be heading to my 8th Fosdem in row.

I went to every single Fosdem so far, some years only one day because of other obligations but I was a round most of the time
During the first couple of years I was pretty active in the FIT team, helping out people to find the right rooms , keeping the fosdem contributions safe with Sven, funding different social events and devroom dinners ,
Later I was in charge of the HPC and Cluster devroom in which we also held the openMosix summits.
And back in 2004 I replaced Moshe at the openMosix Summit standing in front of a great audience at the Janson room.

As Wim just pointed out the Drupal Devroom schedule is out
and it seems like 2008 will be the




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Previous 30 Newer Entries Showing entries 61 to 90 of 102 Next 12 Older Entries

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