Category: Technology

An Intro to Hexadecimal

Introduction

If you work with computers on some level beyond Microsoft Office or browsing the net, at some point, you will run across hexadecimals. What are they and why do people bother using them when they seem something better left for assembly programmers?

Hexadecimal is just a base-16 number system. Because we grew up in a society where most of us has 10 fingers, we use the base 10 decimal system for the most part. In hex, in addition to the numerals 0-9 to represent values zero through nine, we also have letters A-F to represent values ten through fifteen. Continue reading An Intro to Hexadecimal

Virtualization and CPUs

Introduction

In an attempt to better determine how to leverage more CPU power for our virtual server, I started searching to web for beneficial information on adjustments and considerations to make. I was particularly concerned with Hyperthreading at the time. I found a good article by Intel which covers this and more. Check the resources section at the bottom of this article to get more information since they cover many important consideration. I will provide a brief conclusion from information I gained from this article. Continue reading Virtualization and CPUs

Considering RAID Performance on mkfs Command

Introduction

When researching RAID technology, I ran into many concerns regarding performance considerations at multiple levels of storage, including the filesystem. After some research, I found that when creating a filesystem using the mkfs command, the parameters stride and stripe-width can be passed to help the filesystem better accommodate the RAID configuration reads and writes for improved performance. Continue reading Considering RAID Performance on mkfs Command

Selecting the Appropriate RAID Stripe Size

Introduction

After obtaining new equipment, and the new Adaptec 5805Z Raid Controller, I began researching the best configuration of hardware and software from the ground up. Since the machines being setup are storage units, I paid special attention to the RAID controller configuration. This article will address how to select the “best” raid stripe size for your controller. Also, this knowledge is based off of extensive research for two to three weeks, but may have flaws. If any are noticed, please feel free to notify me so that I may review and correct them. Thanks! Continue reading Selecting the Appropriate RAID Stripe Size

Software RAID in FreeBSD

Introduction

FreeBSD provides a helpful tool to manage software RAID with ATA deivces. This tool provides features such as hot swapping ATA RAID devices, which was previously unheard of. This functionality and features will be elaborated here, but caution should be taken as software RAID IS NOT an adequate replacement for hardware RAID. Continue reading Software RAID in FreeBSD

How to restore a corrupt mailboxes.db file for Cyrus IMAP

Introduction

Every once in a while, Cyrus IMAP will die due to a failure in the mailboxes.db file database data. This problem is typically cause by a read/write failure to the mailboxes.db file, which can occur from situations like a power outage during a write to the file. This can lead to corrupt database indexing data in the file. The solution is to process the file as a flat file and extract the valuable data. Since we are aware of the cyrus IMAP mailboxes.db database schema, we can achieve this goal through a script. The following lists the necessary steps to take to extract and rebuild your mailboxes.db file. Continue reading How to restore a corrupt mailboxes.db file for Cyrus IMAP

Remote Differential Compression (Windows 2003, 2008, and Vista)

Introduction

High availability of network services has always been a concern for me. Networks have to operate in a discrete fashion to achieve this goal, requiring many computers have work together to provide a single resulting service. The techniques and procedures involved can drastically vary depending on the nature of the service to provide. I will discuss some details of the Remote Differential Compression technology implemented in Microsoft Windows 2003 and 2008, as well as the new client side support added in Windows Vista. Continue reading Remote Differential Compression (Windows 2003, 2008, and Vista)