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Previous 30 Newer Entries Showing entries 61 to 90 of 1057 Next 30 Older Entries

Displaying posts with tag: Linux (reset)

MySQL, OOM Killer, and everything related
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Do the operating systems kill your MySQL instances from time to time? Are some database servers swapping constantly? These are relatively common problems. Why? How to prevent them?

Memory allocation

When a running program needs some additional memory, it can typically allocate it dynamically with malloc() function. It finds an unused continuous block that is at least as large as the requested size, reserves as much as it needs, and returns a pointer to that space. No initialization of the memory contents is performed at the time. When malloc() returns NULL instead of a valid address, it is an information to the calling program that there wasn’t enough memory available and the call has failed to allocate anything. In such cases applications typically take appropriate actions to notify users about the problem and terminate some of their

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TunnelMaker, a simple script to generate multi-hop SSH tunnels
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SSH tunnels provide a very effective means to access remote services and applications. Not only does it provide encryption of data between hosts, but it allows you to route connections between a sequence of servers, thus chaining connections. A common use of this method is to provide encrypted connections to MySQL servers so that user accounts can be limited to only “localhost” privileges, yet accessed from remote workstations without having to run MySQL+SSL.

The concept is simple, for example let’s say you have three servers: localhost (your workstation in America), a server in Europe, and a server in Japan. You want to access Apache running on port 80 on the Japan server but because of firewall restrictions you cannot access port 80 remotely, and to make things more difficult the Japan server only allows SSH connections from the Europe server’s IP. We can

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Tech Messages | 2012-05-11
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A special extended edition of Tech Messages for 2011-09-21 through 2012-05-11:

Mixed signals in IT’s great war over IP
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Recent news that Microsoft and Barnes & Noble agreed to partner on the Nook e-reader line rather than keep fighting over intellectual property suggests the prospect of more settlement and fewer IP suits in the industry. However, the deal further obscures the blurry IP and patent landscape currently impacting both enterprise IT and consumer technology.

It is good to see settlement — something I’ve been calling for, while also warning against patent and IP aggression. However, this settlment comes from the one conflict in this ongoing war that was actually shedding some light on the matter, rather than further complicating it.

See the full article at TechNewsWorld.

Installing MySQL from source/binary tarball as a Linux service
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I've written before I prefer to do a manual install of MySQL over a repository one. I still do: I typically install from binary tarball or by compiling from source.

I'd like to share my setup procedure for Linux installation and service setup. I've done this dozens of times, on different Linux flavors, and it works well for me.

Installing from source

To get this straight: you sometimes have to compile the source files. I, for example, happen to use the Sphinx MySQLSE extension. You can only use it if compiled with MySQL. You had to compile a "vanilla" 5.1 version without query cache in order to completely remove the cache's mutex contention.

Anyway, I find the easiest way is to install onto a path associated with the server

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CAOS Theory Podcast 2012.04.20
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Topics for this podcast:

*OpenStack, Amazon, Eucalyptus and Citrix engage in open cloud warfare
*Microsoft spins off new company for openness
*Updates on automation players Puppet Labs and Opscode with Chef
*Percona turns attention to MySQL high availability
*Open APIs as the fifth pillar of modern IT openness

iTunes or direct download (28:42, 4.9MB)

Installing MySQL-Frontend Chive (A phpMyAdmin Alternative)
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Installing MySQL-Frontend Chive (A phpMyAdmin Alternative)

This guide explains how to install the phpMyAdmin alternative Chive. Chive is a free, open source, web-based database management tool with easy administration, super fast UI and state of the art web technologies. It takes advantage of the capabilities of modern browsers. Features include an SQL editor with syntax highlighting and built-in profiling of SQL queries.

Analyzing I/O performance
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There are probably thousands of articles on the Internet about disk statistics in Linux, what various columns mean, how accurate the information is, and so on. I decided to attack the problem from a little bit more practical side. Hopefully this will be just the first of many future posts on identifying various I/O related performance problems on a MySQL server.

Linux exposes disk statistics through /proc/diskstats. However the contents of this file isn’t something anyone can understand quickly. It needs a tool to transform the information into something human readable. A tool that is available for any Linux distribution is called iostat and comes with sysstat package.

How to access and read I/O statistics

Usually you want to call iostat one way:

iostat -xkd <interval> <block device>

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Creating a local repository for Yum to work
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You cannot use Yum to an unregistered Linux by default after installation. As a workaround, you will have to create a repo from your installation CD or ISO file.

1. Mount your DVD/CDROM. Run this command from shell.

mount /dev/cdrom /mnt


2. Or if you have no DVD/CDROM, you can copy your ISO file to the server and mount like this.

mount -o loop -t iso9660 yourisofile.iso /mnt


3. Change directory to /mnt and run this command

yum clean all


5. Edit /etc/yum.repos.d/iso.repo. Use nano or vi.

nano /etc/yum.repos.d/iso.repo


6. Paste below and save.

[local]
name=Local CD Repo
baseurl=file:///mnt
gpgcheck=1




























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How to install and configure a Linux server for MySQL?
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Have you ever spent a lot of time thinking about how to install and configure a Linux server for MySQL database? I will try to highlight all the critical steps and some of the decisions you may need to make.

Linux distribution.

Unless you have a really good experience in systems administration, choose a widely supported Linux distribution. The best choices usually are RedHat or its free cousin called CentOS. Compatible alternatives you could also consider are Scientific Linux and Oracle Linux. Make sure you will be installing a 64-bit version, unless you have a very good reason not to.

Storage.

If you have multiple disks available in the server, create a single array from all disks. Choose RAID level that offers

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Fun with Bash :: one liners
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Here are some quick and easy bash commands to solve every day problems I run into. Comment and leave some of your own if you like. I might update this post with new ones over time. These are just some common ones.

Iterate through directory listing and remove the file extension from each file
ls -1 | while read each; do new=`echo $each |sed 's/\(.*\)\..*/\1/'` && echo $new && mv "$each" "$new"; done

Output relevant process info, and nothing else
ps axo "user,pid,ppid,%cpu,%mem,tty,stime,state,command"| grep -v "grep" | grep $your-string-here

Setup a SOCKS5 proxy on localhost port 5050, to tunnel all traffic through a destination server
ssh -N -D 5050 username@destination_server'

Setup a SOCKS5 proxy via a remote TOR connection, using local port 5050 and remote TOR port 9050
ssh -L 5050:127.0.0.1:9050 username@destination_server'

Display text or code file
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How to prevent swapping on a MySQL server?
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Swapping occurs when system moves some data between memory and a special area on disk called swap space. The process is called swapping in or swapping out depending on the direction in which it happens. System swaps out when it makes a decision to free up some physical memory (RAM) and pushes data out to disk. It swaps in when an application needs to access data that was swapped out. MySQL is like any other application and any memory it holds can also be sent to disk. It may have severe negative impact on performance.

The foremost step to prevent swapping is ensuring that not database, not any other application can either independently or collectively use up all available memory. The peak usage may not exceed a threshold that still leaves comfortable buffer for any remaining system activity. If this condition is

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MySQL 5.5 Available on Oracle Linux 6 and RHEL 6
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Following the availability of MySQL 5.5 on Oracle Linux 6 with the Unbreakable Enterprise Kernel, MySQL 5.5 is now also available on Red Hat Enterprise Linux 6 (RHEL 6) and Oracle Linux 6 with the Red Hat compatible kernel.

MySQL users can download MySQL 5.5 Community Edition binaries for Oracle Linux and Red Hat Linux 6 here (http://www.mysql.com/downloads/mysql/#downloads).

MySQL customers can rely on Oracle Premier Support for MySQL when using the MySQL database on either Oracle Linux or Red Hat Enterprise Linux 6.

In addition to offering direct Linux support to customers running RHEL6, Oracle Linux 6, or a combination of both, Oracle also provides Oracle Linux 6 binaries, update and erratas for free via http://public-yum.oracle.com.

How do we control MySQL daemon in Linux, part1
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As you may expect from open source world thingy, almost every Linux distribution has developed it’s own way to manage our favourite RDBMS service. Yet none is perfect, or even some of them seems to not work in real server scenario1.

In this post I’m trying to compare and point out most annoying aspects of initialization scripts that I had to face in production.

In ‘old days’ probably all Linux distributions used to start and stop services using so called init scripts usually written in Unix shell (sh or Bash). But situation is not so simple these days anymore.

Folks started to think about improving things, like making

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Linux gets a bigger shield against patent attacks
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The open source community should feel a little safer from software patent attacks today. The Open Invention Network (OIN), a consortium of Linux contributors formed as a self-defense against software patents, has extended the definition of Linux so that a whopping 700 new software packages are covered, including many developer favorites.

Just one hitch: The new definition also includes carve-outs that put all Linux developers on notice that Phillips and Sony reserve the right to sue over virtualization, search, user interfaces, and more.

read more

Build A Free, Full-Featured Mail Server On Gentoo Linux With iRedMail
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Build A Free, Full-Featured Mail Server On Gentoo Linux With iRedMail

We're going to set up a free, full-featured mail server on Gentoo Linux, all mail service related components are free and open source, and you own all data. The installation process is extremly easy and smooth.

Alias shortcuts to MySQL CLI
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Do you get write laziness in the command line everything what you need to connect to a MySQL server every time?

It may take less than minute, but sometimes one minute is vital (especially if we’re near the end of the world):

ivancp@ubuntu$ mysql -u root -p -h mysqlhost database

When we are hurry, these commands often fail several times per minute.

The solution: we can create shortcuts with bash alias commands in file ~/.bashrc :

# File ~ /. Bashrc
 
# Command "my" to connect to a local server
alias my='mysql -u root -p'
 
# Command "my2" to connect to a remote server
alias my2='mysql -u root -h 192.168.1.56 -p'

Next time if you want to access the local server just type the command my [database name] , there only ask for database password. You can use any command aliases, I

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Moved to a new hosting provider
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Again, I have moved to a new hosting provider after my free-tier with Amazon EC2 expired.  As usual I was looking for a good VPS provider with a decent price, providing good support and in particular a provider supporting FreeBSD, my favorite OS for server (for desktop I still prefer GNU/Linux.)

This time I have carefully reviewed many options and have finally settled with RootBSD, one of the reputed VPS hosting providers if you are choosing FreeBSD as your server OS.  One of the prime reasons for choosing FreeBSD is its performance, stability and the

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Recommendation: Vagrant and Veewee
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Note: I’ve decided not to use Veewee due to silly compatibility issues for now.

Quoting from Vagrant’s web site:

Vagrant is a tool for building and distributing virtualized development environments. By providing automated creation and provisioning of virtual machines using Oracle’s VirtualBox, Vagrant provides the tools to create and configure lightweight, reproducible, and portable virtual environments.

A complementary technology called Veewee makes building VirtualBox VMs easier by automating away a lot of manual steps. Marius Ducea has a great blog post on how to use it.

My observations:
1. According to

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Open APIs are the new open source
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We’ve seen the rise of open source software in the enterprise and also beyond the IT industry, but the real keys to openness and its advantages in today’s technology world — where efficient use of cloud computing and supporting services are paramount — exist in open application programming interfaces, or APIs.

Open source software continues to be a critical part of software development, systems administration, IT operations and more, but much of the action in leveraging modern cloud computing and services-based infrastructures centers on APIs. Open APIs are the new open source.

Read the full story at LinuxInsider.

A great way to test-drive MySQL from MariaDB, Oracle, and Percona
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I was doing some research on Percona Server, and came across this great tip by Baron: if you are using Oracle’s MySQL and want to test out and learn new/improved features that are present in Percona Server, you can just stop the mysqld instance, extract Percona Server binary from its rpm/deb package or tarball file, swap the binary, and do a successful restart. You can then do a test drive, kick the tires, learn and observe to your heart’s content. Swap the original mysqld back after you are done, as necessary.

I tested it and it worked great for me. Specifically, I did the following:
1. sudo /etc/init.d/mysql(d) stop
2. sudo cp /usr/sbin/mysqld /location/mysqldFromOracleOrWhatever
3. sudo cp


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Linux Documentation Writer Wanted!
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The Oracle Linux and Virtualization Documentation Team is seeking an experienced Technical Writer
with a focus on writing documentation for the Oracle Linux product. (The MySQL Documentation Team is part of that group as well.)

Applicants should be located in either Ireland, the UK, Sweden, Norway,


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Linux Documentation Writer Wanted!
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The Oracle Linux and Virtualization Documentation Team is seeking an experienced Technical Writer
with a focus on writing documentation for the Oracle Linux product. (The MySQL Documentation Team is part of that group as well.)

Applicants should be located in either Ireland, the UK, Sweden, Norway,


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M3 code refactor & DBI support
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Pluggable M3 (Monitis Monitor Manager) Framework

Who needs an introduction about M3? – Perhaps no one!
After gaining some reputation with M3, providing extra-easy integration of any monitor into Monitis it was time to take it to the next level.

Generally speaking, the work flow of M3 was described in detail in this article.

After some thought and design, we’ve decided it’d be best if M3 was pluggable. Pluggable in terms of being able to easily add execution and parsing plugins.
The interface and


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CAOS Theory Podcast 2012.01.20
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Topics for this podcast:

*Hadoop v1.0 and year ahead
*Oracle-Cloudera deal for more Hadoop
*Oracle’s ‘Sun spot’ with Solaris
*Open Source M&A outlook for 2012
*Our new MySQL/NoSQL/NewSQL survey

iTunes or direct download (28:49, 4.9MB)

How To Set Up Multi-Master Replication Using Tungsten And MySQL-Proxy For MySQL High Availability On Ubuntu 10.04.3 LTS
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How To Set Up Multi-Master Replication Using Tungsten And MySQL-Proxy For MySQL High Availability On Ubuntu 10.04.3 LTS

This tutorial is based on my experience setting up Tungsten Replicator and MySQL-Proxy for a client's production setup.

SAN vs Local-disk :: innodb_flush_method performance benchmarks
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If you’ve been tuning your MySQL database and have wondered what effect the innodb_flush_method settings have on write performance, then this information might help. I’ve recently been doing a lot of baseline load tests to show performance differences between localdisk and the new SAN we’re deploying. Since we run InnoDB for everything in production, and writes are very heavy, I decided to run comparison tests between two identical servers to find the best setting for innodb_flush_method. We have the following specs for the hardware:

  • Dell R610
  • 24 core Intel Xeon X5670 @ 2.93ghz
  • 72GB ECC RAM
  • Brocade 825 HBA
  • Local disk: RAID-10 15K SAS Ext3 (ugh)
  • SAN: Oracle 7420 with four Intel Xeon X7550 @ 2.00GHz, 512GB RAM, 2TB read-cache(MLC-SSD), 36GB write cache (SLC-SSD), 3 disk shelves populated with 60x2TB 7200RM SATA
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MySQL Performance: Linux I/O
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It was a long time now that I wanted to run some benchmark tests to understand better the surprises I've met in the past with Linux I/O performance during MySQL benchmarks, and finally it happened last year, but I was able to organize and present my results only now..

My main questions were:

  • what is so different with various I/O schedulers in Linux (cfq, noop, deadline) ?..
  • what is wrong or right with O_DIRECT on Linux ?..
  • what is making XFS more attractive comparing to EXT3/EXT4 ?..

There were already several posts in the past about impact on MySQL performance when one or another Linux I/O layer feature was used (for ex. Domas about


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2012 to be year of Linux domination
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Previously, I’ve called out years for non-desktop Linux in 2008, Linux in both the low and high-ends of the market in 2009, ‘hidden’ Linux in 2010 and last year, cloud computing in 2011. For 2012, I see continued growth, prevalence, innovation and impact from Linux, thus leading to a 2012 that is dominated by Linux.

I expect to see nothing but continued strength for Linux and

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The future of commercial open source business strategies
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The reason we are confident that the comparative decline in the use of the GNU GPL family of licenses and the increasing significance of complementary vendors in relation to funding for open source software-related vendors will continue is due to the analysis of our database of more than 400 open source software-related vendors, past and present.

We previously used the database to analyze the engagement of vendors with open source projects for our Control and Community report, plotting the strategies used by the vendors against the year in which they first began to engage with open

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