Linux

Handling the Leap Second – Linux

Leap Second

Last week I published a blog post titled “Are You Ready For the Leap Second?“, and by looking at the blog statistics I could tell that many of you read it, and that’s good, because you became aware of the risks that the leap second on June 30th, 2015 introduces. On the other hand, I…

Are you Ready for the Leap Second?

LeapSecond

If you’re not aware of what the leap second is look into it. The fact is, this year the last minute of June 30th will be one second longer and “June 30, 2015 23:59:60″ will be a valid and correct time. There are a few issues that could be caused by the leap second, so I’ve…

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…

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