Zookeeper Summary

Distributed systems Distributed system involves independent computing entities linked together by network. The components communicate and coordinate with each other to achieve a common goal. In early days, designers and developers often had made some assumptions (aka. fallacies) of distributed computing: The network is reliable Latency is zero Bandwidth is infinite Network is secure Topology … Read moreZookeeper Summary

Virtualization 4 of 4 – Networking

Virtual LAN (VLAN) Although VLAN emerged before virtualization and is not part of virtualization topic. I’d just like to start from here as a refresher. Suppose we have computers from finance department and computers from sales department all connected to a single layer-2 switch. There are at least three problems: 1) too many devices on … Read moreVirtualization 4 of 4 – Networking

Virtualization 3 of 4 – Containers

In broad terms, virtualization of computing resource is about isolation of resources at different levels. We have covered hypervisor-based virtualization in the other post. In this article, we continue to dive into OS level virtualization. Remember again that the gist of virtualization is isolation of resource. To support OS level virtualization, the OS must have … Read moreVirtualization 3 of 4 – Containers

Cloud storage overview

In a narrow sense, cloud storage refers to object storage. In a broader sense, it refers to any storage service (block, file or object level) provided by cloud vendors, in a cloud business model. The underlying technology of storage, is the same be it in the cloud or on-premise. Block storage File storage object Interaction … Read moreCloud storage overview

Virtualization 2 of 4 – Graphics Computing

We covered hypervisor in previous post. In this article we focus on the virtualization of graphics computing resource. GPU vs CPU GPU is a specialized type of microprocessor primarily designed for quick image rendering. GPU appeared as a response to graphically intense applications that put a burden on the CPU and degrated computer performance. They … Read moreVirtualization 2 of 4 – Graphics Computing

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 RPC and therefore one cannot understand NFS without understanding RPC first. In fact NFS is one fo the most prominent user of RPC and a great example for learning RPC. RPC overview On … 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

Docker network

Reading notes of “Docker DeepDive” Docker networking is backed by libnetwork, which is an implementation of Container Network Model (CNM), an open-source pluggable architecture designed to provide networking to containers. Libnetwork also provides native service discovery and basic container load balancing solution. Docker networking also involves some drivers that extend the CNM model with specific … Read moreDocker network

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