A trip to a Wind Farm at Plaine Des Roches

This Sunday the 16th of April, I came across an interesting location in the North-East at Plaine Des Roches, Mauritius where electricity is produced through Wind Farms. The company is Quadran which has invested in this environmental friendly interesting project. Quadran is the global actor in renewable energy encompassing hydroelectricity, solar energy, wind energy and biogas. It has 130 collaborators from 13 agencies and subsidiaries in France metropolitan and Outre-mer including Reunion Island.Quadran. 

The electricity is produced by means of kinetic energy from the wind. The wind turns the blades, which spin a shaft connected to a generator which makes electricity. At some moment, when there is not enough wind, a fuel-powered engine will use switch on automatically for some seconds to run the turbine after which, the wind will take over to turn the blades.

I believe that Mauritius which is looking forward for a more eco-friendly island should invest more in these type of project. This project which involves 11 wind turbines with a power production of 9, 35 MW will satisfy the energy consumption of approximately 10,150 people.

However, side effects of wind turbines are not false. According to some source, there are also reports of negative effects on radio and television reception in wind farm communities. Potential solutions include predictive interference modeling as a component of site selection. A 2007 report by the U.S. National Research Council noted that noise produced by wind turbines is generally not a major concern for humans beyond a half-mile or so. Low-frequency vibration and its effects on humans are not well understood and sensitivity to such vibration resulting from wind-turbine noise is highly variable among humans. – www.nap.edu

Hackers.mu attracted a massive crowd at the DevConMru 2017

This is yet another dazzling inspiration that hackers.mu brought into the mind of the audience today on the 1st of April 2017 at the DevConMru – Day 2. After the mesmerising speech at the DevConMru by Logan, this time Codarren Velvindron, core member of hackers.mu hit the conference room with so many attendees. Fast Coding Skills – A well chosen topic especially for the curious ones, beginners or professionals who want to remove the barrier between the code and them. Codarren started the presentation by giving some examples about the applications he ventured into, for example MariaDB.

The room was full with over fifty attendees. While some were sitting on the floor, others leaned up against the wall focussed on Codarren. I heard someone from the crowd murmuring “I want to be a hacker”.. 🙂

Several analogies were brought to the attention of the audience such as the difficulties which one has to encounter whilst coding. Tips and tricks to get relief from these difficulties were offered; such as playing, breaking the huge task into parts and analysing the mini parts of each. Another way to understand how the code works is by “deleting” part it after a backup to know how it would behave in a different environment. Codarren also shared his experience about the IETF hackathon in which he participated.

Here is the Slide of Codarren at the DevConMru 2017

Fast Coding Skills by Codarren Velvindron on Scribd

At the end, we thanked Codarren for the job done. Members of hackers.mu kept on responding to people from the audience who were showing interest in coding. Some questions from the audience were about the challenges faced in the IETF hackathon as well as Codarren’s favourite programming language. “Talk is cheap, show me the code” – Linus Torvalds.

Hackers.mu mesmerising speech at the DevConMru 2017

The message was clear and direct at the DevConMru 2017. Painted with a humorist approach, Loganaden Velvindron #2 of hackers.mu bridged the gap between students who were mainly in the audience to reach their goal in the IT industry and Linux in Mauritius.

The DevConMru is a yearly event to bring together developers, beginners, students and professionals. The goal is to bring more craftsmen under the same roof. “Mauritius has been branded “Cyber Island” in the Indian Ocean… Opinions in those matters vary but with this conference we strive to improve the general attribution of our island. Mauritius has great political stability and economical advantages for foreign investors, and the most precious resource Mauritius has to offer is people’s knowledge. The ICT sector in Mauritius is growing since years and maturing as the fourth pillar of our economy. With its geographical position Mauritius is also welcome as a business and knowledge hub between Africa and Asia.”MSCC.

In today’s Mauritius IT industry, everyone wants to have a better standard of living. But how? How to build a successful IT industry? Are we moving in the right direction? Are foreign investors attracted by the quality of the Mauritius IT industry ? Logan did not miss those points to bring the audience on the track.

Photo Credits: Hackers.mu
Photo Credits: Hackers.mu

After giving a brief intro of the hackers.mu team, Logan explained the requirements and life cycles of IT companies and their profits as to whether they are in the same line of fresh IT graduates and professionals. A vivid example is by analyzing the statistics of Github accounts in Mauritius, the quality and quantity of code contribution compared with Singapore. Students were encouraged to publish their coding exercise on GitHubs, create a blog and take part in Google Code-in.

Indeed, hackers.mu work towards such goals, for example, participation and mentoring for the Google Code-in. Several hackathons were organised. Contributions in the real world applications such as Pfsense, OpenSSH, OpenSSL, OpenBSD, LibArchive, Firejails, Linux and others.. This list is long. An award was also received during the IETF 98 Hackathon.

Logan at the DevConMru 2017
Logan at the DevConMru 2017

The slide can be viewed here or on the Scriba website.

I was impressed how Avinash Meetoo, honorary member of the hackers.mu hacked the audience and shed some light to boost the students. Avinash mentioned himself about his passion for blogging and the importance of projecting his personality with the right vision.

At hackers.mu, we invite many to join us, but one have to work hard to attain a certain level of professionalism.  After the presentation, many came to congratulate us for the job done. We were around chatting with many sharing our work and job experience as well as the passion for coding. I once read a phrase in an old book as follows “You are what you eat”.  But things have change now because You are what You CODE!!

Recovery Data and Applications with Zerto – Part 2

The flexibility of Zerto Virtual Replication means that we have multiple options for data recovery depending on what’s specifically needed in each use case. ZVR enables data mobility by adding offsite cloning to the toolkit. You have the ability to restore specific files and folders. Now if a critical folder is inadvertently erased, the clock can be rewind by saving time and money.

JLFR -Journal Level File Restore is a powerful feature that extends Zerto’s protection features to allow recovery of individual files or folders. Restoring a file uses the same checkpoint system to facilitate point in time selection and recovery. Any files in the journal can be recovered with the journal sizing tool. JLFR requires NTFS or FAT and is thus Windows compatible only.

To restore a file, click on “Actions” and then on the “Restore File” button.

Photo Credits: Zerto.com
Photo Credits: Zerto.com

Select the ZFileServer and click on next

Photo Credits: Zerto.com
Photo Credits: Zerto.com

Files can be restored from the available checkpoints.

Photo Credits: Zerto.com
Photo Credits: Zerto.com

The disk need now to be mounted whether physical or virtual that stores the files or folders to recover. Only one disk at a time can be recovered.

Photo Credits: Zerto.com
Photo Credits: Zerto.com

After that, the mount process can start.

Photo Credits: Zerto.com
Photo Credits: Zerto.com

As usual, the running tasks will be shown running on the dashboard. There are few ways to start restoring files and folders from the mounted disk, including from the monitoring tab or the open folder icon on the right under the running tasks.

For example on the bottom, there is a tasks button.

Photo Credits: Zerto.com
Photo Credits: Zerto.com

The browse button allows you to search for the files and restore it. Once finish click on the unmount button.

Photo Credits: Zerto.com
Photo Credits: Zerto.com

Another feature is cloning – Cloning will create a copy of the virtual machines saved to a specific point-in-time checkpoint.

By selecting the VPG name from the VPG tab which will open the VGS’s name in another tab. Click on More then on offsite clone.

Photo Credits: Zerto.com
Photo Credits: Zerto.com

Once on the Offsite Clone tab, click on Select a checkpoint.

Photo Credits: Zerto.com
Photo Credits: Zerto.com

For example, by selecting the latest checkpoint and the name of the Datastore, we can start the cloning operation.

Another recovery option is the backup restore. This is done by clicking on Actions then on Restore Backup. Again from some options, few things need to be checked. By choosing the restore plan which is the name of the VRA, the restore point, VM settings and the Power On option.

Photo Credits: Zerto.com
Photo Credits: Zerto.com

And finally the Restore Button

Photo Credits: Zerto.com
Photo Credits: Zerto.com

Restoring from backup allowed you to leverage scheduled and unscheduled backups that extend the protection offered by the journal. Cloning extends ZVR by  giving you multiple copies of your machines as they looked at a very specific point in time. With the file restore feature, you can extend the functionality of ZVR across the full spectrum of disaster recovery options, ranging from recovery of an entire virtualized datacenter to recovery of just one single file.

SAR command daily tips and tricks

As promised on Twitter days back, I would post some interesting tips and tricks using the SAR (System Activity Report) linux command. The sar command writes to standard output the contents of selected cumulative activity counters in the operating system. The accounting system, based on the values in the count and interval parameters, writes information the specified number of times spaced at the specified intervals in seconds. If the interval parameter is set to zero, the sar command displays the average statistics for the time since the system was started.die.net 

Understanding SAR and its main configuration files

The SAR command is part of the sysstat package which is a multi-purpose analysis tool and it is useful to pin point specific issue related to CPU, Memory, I/O and Network. The command is really useful especially to plot the output on a graph for visual analysis and reporting. One example of such tool is GNUplot. To install GNUplot and SAR use the command yum install sysstat gnuplot. The configuration file of SAR is located at /etc/cron.d/sysstat and /etc/sysconfig/sysstat . If you would perform a rpm -ql sysstat | less , you would noticed that there are other binaries such as iostat,mpstat,pidstat etc.. that comes along with the package sysstat.

Difference between SA and SAR logs

In the directory /etc/cron.d/sysstat you would noticed that there is a cron which have been set up by default to run every ten minutes. The purpose is to write a log in the directory /var/log/sa . In this directory there are two type of files starting with sa and sar. SAR is the text file while SA is a binary. The sa file – Binary is updated every 10 minutes whereas the sar file is written at the end of the day. This parameter have been configured in the cron itself. By using the file command you would know which one is a binary or a text file.

To open the sa file, you need to use the command sar -f . Here is an example:

The /etc/sysconfig/sysstat file allows you to configure how long you want to keep the log, compression etc..

Some ways to use the SAR command

You can also visualize sar logs live using the sar command with the start and ending second. Let’s say you have run a command on the background or simply want to track the resource status for some seconds, you can use the command sar 1 3 Here is an example with the command

sar 1 3

Checking the load average, we apply the same principle but with the following command. The load average will also include load on each processor.

sar -q 1 3

To check for memory being consumed per seconds, use the following command

sar -r 1 3

To check number of memory coming in and out of the swap space, use the following command

sar -W 1 3

For the Disk I/O read write per seconds use the following command. Read/Write on disk also depend on the hardware

sar -b 1 3

For info about the CPU use the following

sar -u 1 3

To monitor the network activity in terms of packets in and out per interface received and compressed, use the following command

sar -n DEV 1 3

If the sar file has not been generated yet from the binary, you can use the following command, let’s say to convert it to a text in the /tmp directory.

sar -A -f  sa25 > /tmp/sar25

KSAR Graph with SAR logs

Now, in production environment, you need to to analyze for example at a specific time where memory or CPU was high. This can be done by means of a graph. I use the Ksar program. Ksar is a BSD-Licensed JAVA based application which create graph based on sar logs. You will need to install JAVA Runtime and launch the run.sh script to install the Ksar program. Once downloaded, just click on ‘Data’ and ‘Load from text file’. This is an example of swap usage


  • The SAR output by default is in 12 hour clock format. To make it become a 24 hour clock format edit the .bashrc file and insert the parameter alias sar=”LANG=C sar
  • GNUPlot is one another application to plot your information on a graph for better analysis.