Nov 272010
 

DRBD
You may need to have information replicated between two computers that actually are part of a cluster, in addition to”software” replica mechanisms such as Rsync you can use a product that is stable and included in the standard kernel: DRBD.

DRBD (Distributed Replicated Block Device) is a distributed storage system for the GNU/Linux platform. It consists of a kernel module, several userspace management applications and some shell scripts and is normally used on high availability (HA) clusters. DRBD bears similarities to RAID 1, except that it runs over a network.

DRBD refers to both the software (kernel module and associated userspace tools), and also to specific logical block devices managed by the software. DRBD device and DRBD block device are also often used for the latter.

It is free software released under the terms of the GNU General Public License version 2. Continue reading »

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Nov 182010
 

history

The history command is very useful when you frequently work at the terminal and you want to invoke a command given in the past.But there are several options that are not so common or poorly understood, in this article we’ll see some of them in bash and zsh.

Basic usage

Show last commands in history.

Apply to bash and zsh

history

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Nov 092010
 

linux serial

Automatically Capturing, Saving and Publishing Serial RS232 Data to the Web

Author: John Smitty

This article will describe setting up a system that will utilize a lightweight command line (CLI) install of Linux (Ubuntu in this example) to capture RS232 (serial) information, capture it and upload it to an ftp server.

This is useful for applications including data collection from sensors or other serial devices such as amateur packet radio – and will utilize the data on a web site or other remote machine.

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Nov 042010
 

lvs Linux Virtual Server, LVS is an advanced load balancing solution for Linux systems. It is an open source project started by Wensong Zhang in May 1998. The mission of the project is to build a high-performance and highly available server for Linux using clustering technology, which provides good scalability, reliability and serviceability.

The major work of the LVS project is now to develop advanced IP load balancing software (IPVS), application-level load balancing software (KTCPVS), and cluster management components.

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