Every step of progress the world has made has been from scaffold to scaffold, and from stake to stake.

Wendell Phillips

If you want to know about Scaffold and its importance in flutter then you are probably in the right place. I have also written a small introduction about Flutter and its widgets. If you don’t know about the technology, have a read.

What is Scaffold?

  • A widget
  • A framework that implements the basic material design visual layout structure.
  • A class that provides APIs for showing drawers, SnackBars, and bottom sheets.
//Constructor of Scaffoldconst Scaffold({
Key key,

Geo-replication image
Geo-replication image

In the last blog, we went through the basics of Geo-replication and its different deployment services. In this blog, we will be going through the setup step-by-step. 🚶


You have at least 2 Virtual Machines (VMs). One of them will hold the main volume 💾 and the other one will hold the secondary volume 💾. We will be setting up geo-replication on these two volumes only.

Let’s start with the setup now 😄


  1. Create 2 volumes. If you want to know how to set up volumes refer to this article

This is with replica volume. With just 2 servers you…

RPM-Redhat Package Manager

Contents 📑

  1. What is an RPM?
  2. Compiling RPMs on Fedora, CentOS and RHEL.
  • Preparatory Steps
  • Common Steps

What is an RPM?

RPM Package Manager (RPM) (originally Red Hat Package Manager, now a recursive acronym) is a free and open-source package management system.[5] The name RPM refers to .rpm file format and the package manager program itself.

An RPM package can hold an arbitrary set of files. Most RPM files are “binary RPMs” (or BRPMs) containing the compiled version of some software. There are also “source RPMs” (or SRPMs) containing the source code used to build a binary package.

Wikipedia 💻

Compiling RPMs on Fedora, Centos, and RHEL

In this article we will…

What is Quota?

Dictionary Meaning: 📓

A limited quantity of a particular product which under official controls can be produced, exported or imported.

In terms of storage: 💾

A quota is a fixed amount of storage that can be consumed by an individual to store data on the file system. It can be used to set storage limits on directories.

I hope so this explains well.

Quota as a feature — Gluster 🐜

Directory quotas in GlusterFS allow you to set limits on the usage of the disk space by directories or volumes. The storage administrators can control the disk space utilization at the directory and/or volume levels in GlusterFS…


What is Geo-replication?

Geo-replication systems are designed to enhance the distribution of data across geographically distributed data networks. This is aimed to improve the response time for applications such as web portals. Geo-replication can be achieved using software, hardware, or a combination of the two.

Gluster and Geo-replication

Geo-replication gives a distributed, continuous, asynchronous, and incremental replication service from one site to another over Local Area Networks (LANs), Wide Area Networks (WANs), and the Internet.

Geo-replication uses a primary-secondary model, where replication and mirroring occur between the following partners:

  • Primary — a GlusterFS volume. [Primary volume]
  • Secondary — a GlusterFS volume. [Secondary volume]


On running gluster volume geo-replication <main vol> <secondary-host>::<secondary volume> start you get

geo-replication start failed for <primary vol> <secondary host>::<secondary volume>
geo-replication command failed


OSError: libgfchangelog.so.0: cannot open shared object file: No such file or directory.

Log File 📁

/var/log/glusterfs/geo-replication/<main vol>_<secondary host>_<secondary_vol>/gsyncd.log

You can cat the above file and find the following error mentioned above.

Fix 🔧

  1. Try rebooting glusterd service glusterd restartand check.
  2. If it doesn’t work. Follow the following procedure:
root@user# cd /etc/ld.so.conf.d/root@user /etc/ld.so.conf.d# vi myconfig.conf
  • Press I or Insert to start writing.
  • Add the following lines:
  • Press Esc
  • Type :wq and press Enter
  • Run the following command
root@user /etc/ld.so.conf.d# ldconfig

Read before


an application, or a component of an interface, that enables a user to perform a function or access a service : Dictionary

In simpler terms, a widget in flutter is the same as a container. Basically, a clay container that you can change or alter dynamically as per your need with few restrictions. Web developers would be already familiar with the word ‘container’, so it would be easy for them to catch up with the word widget.

Flutter widgets are built using a modern framework that takes inspiration from React. Widgets help you in development of your UI for your…


“Apps take flight with flutter”

Flutter is a new app development technology.

That will be an understatement for flutter.

Flutter is an open-source UI software development kit created by Google. It is used to develop applications for Android, iOS, Windows, Mac, Linux, Google Fuchsia and the web from a single codebase

Ayush Ujjwal

Flutter | Google Actions | Gluster

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