Virtualization 1 of 4 – Hypervisor

In broad terms, virtualization of computing resource is about isolation of resources, at different levels. There are five levels of virtualization: Application level, such as JVM, .NET CLR Library (user-level API) level Operating system level, such as LXC, Docker, OpenVZ Hardware abstraction layer (HAL) level, such as VMware, Xen, etc Instruction set architecture (ISA) level … Read moreVirtualization 1 of 4 – Hypervisor

How NFS works

I touched on NFS in several previous postings, and here is a deeper dive of this particular protocol. NFS is built on top of Remote Procedure Call (RPC) and therefore it is important to understand RPC first. In fact NFS is one of the most prominent user of RPC and the best example for learning … Read moreHow NFS works

EMC Isilon

EMC has several product lines for different use cases in enterprise data storage. Like may other IT solutions, the website is clouded with marketing terms and slogans, and is purposefully not technical. This makes it difficult for technical staff to grasp the advantage of its product in a glimpse. I personally have to know their … Read moreEMC Isilon

Performance Analysis

Overview In 2015, Brendan Gregg posted two great articles on Netflix blog: Linux Performance Analysis in 60 seconds, and Linux Perfomrance Tools. They have great value when I was in a urgency to spot performance issues. The articles cover the essential tools for performance troubleshooting, including: Check out load averages: w or uptime Print kernel … Read morePerformance Analysis

Capture filter and Display filter in Network Analyzer

Capture filter is set before collecting packets. It is applied at the time of data acquisition and it impacts the size of the capture. It does not have as many variations as display filter and is usually not aware of protocols above TCP/UDP layer. A common form of capture filter is BPF (Berkerly Packet Filter) … Read moreCapture filter and Display filter in Network Analyzer

Introduction to Authentication Frameworks (PAM and SSPI)

This article gives a very brief high-level introduction to PAM (Pluggable Authentication Module) and SSPI (Security Support Provider Interface) as authentication frameworks in Linux and Windows respectively. PAM The Pluggable Authentication Module (PAM) architecture provides a powerful abstraction for user IAM using pluggable authentication model Unix platforms. It defines a generic API for authentication and … Read moreIntroduction to Authentication Frameworks (PAM and SSPI)