Enterprise Infrastructure

fsfreeze in Linux

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…

Using strace to debug application errors in linux

strace is a very useful tool which traces system calls and signals for a running process. This helps a lot while debugging application level performance issues and bugs. Aim of this post is to demonstrate the power of strace in pinning down an application bug. I came across an issue in which nagios was sending…

Troubleshooting a Multipath Issue

Multipathing allows to configure multiple paths from servers to storage arrays. It provides I/O failover and load balancing. Linux uses device mapper kernel framework to support multipathing. In this post I will explain the steps taken to troubleshoot a multipath issue. This should provide an glimpse into the tools and technology involved. Problem was reported…

Deploying a Private Cloud at Home — Part 7

Welcome to part 7, the final blog post in my series, Deploying Private Cloud at Home, where I will be sharing the scripts to configure controller and computer nodes. In my previous post, part six, I demonstrated how to configure the controller and compute nodes. Kindly update the script with the password you want and then execute. I am assuming…

Deploying a Private Cloud at Home — Part 6

Today’s blog post is part six of seven in a series dedicated to Deploying a Private Cloud at Home, where I will be demonstrating how to configure controller node with legacy networking ad OpenStack dashboard for webgui. Feel free to check out part five where we configured compute node with OpenStack services. First load the admin variables…

Deploying a Private Cloud at Home — Part 5

Today’s blog post is part five of seven in a series dedicated to Deploying Private Cloud at Home, where I will be demonstrating how to configure Compute node and OpenStack services on the compute node. We have already installed the MySQL Python library on compute node in previous posts. Install OpenStack compute packages on the node yum…

Service Reliability: How Systems Administration is Evolving – Part One

The world of systems administration is changing, and it’s affecting everyone involved. Today’s blog post is the first of two in mini-series dedicated to Service Reliability: How Systems Administration is Evolving. The days of formulas that tell us, You need “X” system admins, for every “Y” physical server, and every “Z” VMs are coming to…

Internet Scale Design: Part Two

In my previous blog post, I emphasized that internet scale design can be implemented for any type of company. Whether it’s a small, bootstrapped startup or a rapidly growing, well-funded tier 2. But if it’s suitable for that many companies, why isn’t everyone moving into the cloud? In my opinion, there are two reasons. First,…

Internet Scale Design: Part One

Internet Scale graphic 1

Whether your company is a small, bootstrapped startup or a rapidly growing, well-funded tier 2 or 3 business, everyone dreams of having ‘Internet scale’ systems which are highly automated, anti-fragile, self-healing, and inexpensive to maintain. The problem, however, is that those types of complex systems are only within the reach of well-funded companies who can…