Mohan Cheema's Online Diary

Everyone probably know about memcached (http://memcached.org/) and its high performance name-value based memory object cache interface. Its main purpose is to provide an easy to use distributed caching engine in a multinode environment. However, have you ever wanted to let memcached handle replication?

If you’d like to add high-availability capabilities, you’re advised to let the client (-library) handle replication of your data throughout all nodes. Let’s say using memcached as storage backend for php sessions is configured as follows:  Read more...

Different platforms and devices require SSL certificates to be converted to different formats. For example, a Windows server exports and imports .pfx files while an Apache server uses individual PEM (.crt, .cer) files.

PEM Format
The PEM format is the most common format that Certificate Authorities issue certificates in. PEM certificates usually have extentions such as .pem, .crt, .cer, and .key. They are Base64 encoded ASCII files and contain “—–BEGIN CERTIFICATE—–” and “—–END CERTIFICATE—–” statements. Server certificates, intermediate certificates, and private keys can all be put into the PEM format.  Read more...

Introduction

In many cases using MRTG in a basic configuration to monitor the volume of network traffic to your server isn’t enough. You may also want to see graphs of CPU, disk, and memory usage. This chapter explains how to find the values you want to monitor in the SNMP MIB files and then how to use this information to configure MRTG.

All the chapter’s examples assume that the SNMP Read Only string is S3c999rity and that the net-snmp-utils RPM package is installed

Locating And Viewing The Contents Of Linux MIBs  Read more...

Introduction

You can monitor your system’s Web performance quite easily with graphical Linux tools. You’ll learn how to use several in this chapter, including MRTG, which is based on SNMP and monitors raw network traffic, and Webalizer, which tracks Web site hits.

SNMP

Most servers, routers and firewalls keep their operational statistics in object identifiers (OIDs) that you can remotely retrieve via the Simple Network Management Protocol (SNMP). For ease of use, equipment vendors provide Management Information Base (MIB) files for their devices that define the functions of the OIDs they contain. That’s a lot of new terms to digest in two sentences, so take a moment to look more closely.  Read more...

Subversion ADS Authentication with Apache

More and more companies are using directory services for housing their user credentials and information. Example directory services are Active Directory, eDirectory and OpenLDAP.

How does this relate to Subversion? Well, in the enterprise deployments I’ve been involved with, most clients wanted to harness their existing directory services for their Subversion authentication. This document will provide the instruction on how to make apache use Windows AD Services for authentication. These steps have been tried and tested on RHEL 4 AS. Compilation and installation steps may differ from unix to unix.  Read more...