The fsfreeze command, is used to suspend and resume access to a file system. This allows consistent snapshots to be taken of the filesystem. fsfreeze supports Ext3/4, ReiserFS, JFS and XFS.

A filesystem can be frozen using following command:

# /sbin/fsfreeze -f /data

Now if you are writing to this filesystem, the process/command will be stuck. For example, following command will be stuck in D (UNINTERUPTEBLE_SLEEP) state:

# echo “testing” > /data/file

Only after the filesystem is unfreezed using the following command, can it continue:

# /sbin/fsfreeze -u /data

As per the fsfreeze main page, “fsfreeze is unnecessary for device-mapper devices. The device-mapper (and LVM) automatically freezes filesystem on the device when a snapshot creation is requested.”

fsfreeze is provided by the util-linux package in RHEL systems. Along with userspace support, fsfreeze also …

Foto: Ana Rey CC-BY-SA-2.0El “Concurso Universitario de Software Libre” (CUSL) es una iniciativa similar a la del Google Summer of Code, pero específicamente dirigida la comunidad universitaria y de estudiantes de bachillerato españoles y organizada por una grupo de Oficinas de software libre de universidades.

Como parte del esfuerzo para promover el crecimiento del ecosistema del software libre, así como introducir a talento joven en el desarrollo de aplicaciones y tecnologías libres, DBAHire.com acaba de convertirse en patrocinador plata de la competición, proporcionando recursos para los premios, gastos de …

Daniel was tracking down what appeared to be a networking problem….

• server reported 113 (No route to host)
• However, an strace did not reveal the networking stack ever returning that.
• On the other side, IP packets were actually received.
• When confronted with mysteries like this, I get suspicious – mainly of (fellow) programmers.
• I suggested a grep through the source code, which revealed  return -EHOSTUNREACH;
• Mystery solved, which allowed us to find what was actually going on.

Lessons:

1. Don’t just believe or presume the supposed origin of an error.
2. Programmers often take shortcuts that cause grief later. I fully appreciate how the above code came about, but I still think it was wrong. Mapping a “similar” situation onto an existing …

In the beginning was the MySQL command line and it was good. Verbose yes, error prone yes, and even tedious. But it was good. The UPDATE USER set SELECT_PRIV=’Y’, DROP_PRIV_’Y”, UPDATE_PRIV=’Y’,……,LAST_BLOODY_PRIV=’Y”; type errors have caught of us old timers. But it was still good.

Then came some GUI tools that were okay. Not great but they had their uses.

And then came MySQL Workbench. And it was very good.

Now there is MySQL Workbench 6.2 and it is excellent. It came out in Beta last week and has built on the proven success of its predecessors. All the usual stuff is there – Server Status, Users & Privileges, Startup/Shutdown, logs, Dashboard, Performance Reports and more. But there area whole bunch of subtle little tweaks that make it easier to use.

For instance, the VISUAL EXPLAIN allows toggling between the visual display and the tabular display. Plus you can now get query …

“There are four things that motivate open source development teams:
1. The challenge/puzzle of programming, 2. Need for the software, 3. Personal advancement, 4. Belief in open source” — Bruce Momjian.

On PostgreSQL and the challenges of motivating and managing open source teams, I have interviewed Bruce Momjian, Senior Database Architect at EnterpriseDB, and Co-founder of the PostgreSQL Global Development Group and Core Contributor.

RVZ

Q1. How did you manage to transform PostgreSQL from an abandoned academic project into a commercially viable, now enterprise relational database?

Bruce Momjian: Ever since I was a developer of database …

I wrote previously about Percona Live Santa Clara 2014, and I want to bring to your attention something Percona has done that is very nice to open source communities: have an open source appreciation day.

Its before the conference (so on Monday), and you get a choice between the CentOS Dojo (great lineup there including many from Red Hat, Monty from MariaDB, and PeterZ from Percona) or the OpenStack Today (another great lineup …

The wild and crazy guys over at S&T Geotronics, James Sanderson and Marc Tessier, have decided to go full tilt with a Kickstarter version of their DIY Open Enigma Project.  For those who missed the fanfare last year, they were featured on Instructables showing how to build an Arduino-based encryption machine that works exactly like a WWII era Enigma.  You know, the thing that Alan friggin' Turing and his team at …

On the road again - FOSSAsia

It has been a few busy months until now. I have moved from Italy to Thailand, and the move has been my first priority, keeping me from attending FOSDEM and interacting with social media. Now I start catching my breath, and looking around for new events to attend. But before I get into this, let’s make a few things clear:

• I am still working for Continuent. Actually, it’s because of my company flexibility that I could move to a different country (a different continent, 6 time zones away) without much trouble. Thanks, Continuent! (BTW: Continuent is hiring! )
• I am still involved with MySQL activities, events, and community matters. I just happen to be in a different time zone, where direct talk with people in Europe and …

It's my pleasure to be presenting at SCaLE 12X on the subject of real-time data loading from MySQL to Hadoop.  This is the first public talk on work at Continuent that enables Tungsten Replicator to move transactions from MySQL to HDFS (Hadoop Distributed File System).  I will explain how replication to Hadoop works, how to set it up, and offer a few words on constructing views of MySQL data using tools like Hive.

As usual with replication everything we are doing on Hadoop replication is open source.  Builds and documentation will be publicly available …

There is a good article over at Re-Code by ex-Microsoft VP Steven Sinofsky called "The Four Stages of Disruption".  It describes the evolution of products and markets through disruption, drawing from Sinofsky's own insights and also building on the work of Everett Rogers ("The Diffusion of Innovations") and Clayton Christensen ("The …