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Displaying posts with tag: Linux (reset)
Fedora R Install

I’ve started building the new image for the database courses. This one needs to include Oracle, MySQL, Cassandra, Hive, and MongoDB databases; and include examples for C, C++, Java, Perl, PHP, Python, R programming languages.

Installing R was a surprise when I saw how many packages there are for it. It’s a standard yum command from the repository, but it will install 256 packages. The command is:

yum install -y R

Once you install it, you simply start the R interpreter, which is part of the Comprehensive R Archive Network (CRAN). Any installation of the R packages includes CRAN, but there are many additional libraries that you may install.

You can launch the R interpreter by typing the following at the Linux command-line:


It will display the following licensing information and then the command prompt:

R version 3.2.0 (2015-04-16) -- "Full of Ingredients"
Copyright (C) 2015 …
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Ansible Best Practices

Managing Heterogeneous environment without automation can be tricky. We are using Ansible as an automation tool for install, configure and manage DB infra for Mydbops. Using Ansible, we overcome a lot of obstacle’s and we would like to share our learning with the community ( Our Presentation on Ansible )


Best Practices to write Ansible Plays

Use Native YAML Syntax

Ansible Tasks and Playbook are written in YAML. We can format YAML in different ways

  1. shorthand/one-line (=)
  2. structured map (:)
  3. folded scalars (>)

Shorthand/one-line (=)

- name: …
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Tungsten Clustering 6.0 and Tungsten Replicator 6.0 are now available!

Continuent is very pleased and excited to announce that the new Tungsten Clustering 6.0 and Tungsten Replicator 6.0 are now available for download by our customers. The 6.0 release is the culmination of over a years work within our clustering product in order to improve the functionality and manageability of what we now call our ‘Multimaster Clustering’ solution. This is the replacement for what we called the multi-site, multi-master (MSMM) clustering functionality in earlier releases. The multimaster clustering allows for multiple clusters, in multiple locations, to be linked together into a single composite cluster. Because it’s a composite cluster, you gain all of the functionality that’s already available in a cluster, such as:

  • High availability
  • Failover
  • Automated recovery
  • Read-write split
  • Maintenance without downtime

But it’s now applied to the …

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Docker Compose Setup for InnoDB Cluster

In the following we show how InnoDB cluster can be deployed in a container context. In the official documentation (Introducing InnoDB Cluster), InnoDB is described as: MySQL InnoDB cluster provides a complete high availability solution for MySQL. MySQL Shell includes AdminAPI which enables you to easily configure and administer a group of at least three […]

Handling long duration SST(timeout) in PXC with systemd

In this blog post, We will be explaining about the timeouts in SST on systemd implementation which we faced recently in Percona XtraDB Cluster  during our Consulting with a client. State Snapshot Transfers (SST) refers to complete data sync from one of the nodes from the cluster to the joining node.

SST will happen for one or more reasons listed below.

  1. Initial sync to join a node to cluster.
  2. Node is out of cluster and lost its ability to join back due to data corruption or inconsistencies and also when the node went far behind the node, …
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MariaDB source visualisation with Gource

Gource is a tool which can take a source code tree and create beautiful visualisations out of it. I’ve used it a few times before for various projects. This weekend I spent a little bit of time playing with it and applying it to MairaDB Server to see what it would produce.

The end result can be seen on YouTube.

In this visualisation you can see every file in the source code as a coloured dot. The dots are clustered in directories which are linked together in the directory tree using the lines. Git users swam around the files and spray code into them. It gives you a real sense of just how much work goes into a project.

To create this I got the MariaDB tree from GitHub and switched to branch 10.3. I observed the first MariaDB 5.1 tag was on the date 26th …

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How to convert galera node to async slave and vice-versa with MariaDB Galera Cluster.

Recently, I was working with one of our customer and this is what their requirement as they want to automate this process for converting galera node to async slave and make async slave to galera node without shutting down any server. ———- Here are the steps for how to do that. I assumes that you already have working 3 nodes galera cluster if not, then for the testing purpose you can create it from my previous post. setup-three-nodes-mariadb-galera-cluster-on-single-server-with-mysql-sandbox ———- Btw, there is no matter how many nodes you have. Now, create one test1 table and add 3 records in galera cluster.

MariaDB [nil]> select * from test1;
| id   | name      |
|    1 | nilnandan |
|    2 | joshi     |
|    3 | niljoshi  | …
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Making Maxscale/ProxySQL Highly Available ( 2 > 1 )

As Mydbops we are implementing Load Balancer using Maxscale or ProxySQL ( Our presentation ) for lot our client,  but these load balancers will become a SPOF (Single Point of failure) .  We have tried to explore services like HAProxy, Nginx, and Keepalived etc. Except Keepalived, all the services need to run on the standalone instance and  did not satisfy our exact need.

Keepalived does not requires any standalone instance, it can be deployed and configured with a minimal effort and provide the HA Solutions to the DB Infra. This approach not only fits for our DB setup, we can implement same …

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CPU Utilization is Not a Useful Metric

Once upon a time CPU utilization was quite a useful metric. Following are the output of several tools that provide CPU utilization metrics:


top reports a load of 1.66.

Is this correct? No. The correct load number is probably closer to 2.4.

# top -b -n 1| head -20
top - 11:27:45 up 151 days,  1:55,  7 users,  load average: 1.66, 1.84, 1.88
Tasks: 389 total,   3 running, 386 sleeping,   0 stopped,   0 zombie
Cpu(s):  0.7%us, 20.6%sy,  1.2%ni, 77.3%id,  0.1%wa,  0.0%hi,  0.1%si,  0.0%st
Mem:  32639636k total, 32206476k used,   433160k free,   235732k buffers
Swap: 16359420k total, 10285664k used,  6073756k free,  2354840k cached

16702 root      20   0 8274m 5.0g 5.0g S 85.1 16.1  59164:55 VirtualBox
 4657 root      20   0  9.8g 5.2g 5.1g S 45.5 16.6  26518:13 VirtualBox
 6239 root      20   0  9.8g 5.1g 5.1g S 39.6 16.5  31200:52 VirtualBox
27070 root …
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Donkey System

Donkey system is a fully automatic MySQL database change system.
It gives a great help both to the release of the business and the company’s automated operation and maintenance.


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