RAID 5

RAID 5 is level of RAID that combines both block-level striping and distributed parity among the array.  A standard RAID 5 array uses three disks. Data is striped in blocks, written to two of the disks, similar to RAID 0. The third disk receives parity information about the blocks of data. In RAID 5 the […]

RAID 1

RAID 1, also known as disk mirroring, is a level of RAID in which data is duplicated on both disks of an array. RAID 1 requires two disk volumes in the array. With RAID 1, each disk is a mirror of the other disk. Because disks are mirrored, there will need to be an even […]

RAID 0

RAID 0, also known as disk striping, is a level of RAID that distributes blocks of data to the disks within the RAID. This level of RAID can be accomplished using two or more disk drives. With RAID 0, the blocks of data are roughly distributed equally among each of the disks. The storage capacity […]

The Apache Configuration File

The main configuration file for Apache is located at /etc/apache2/apache2.conf. Apache may work a little different on Ubuntu (and other Debian based distributions) than other operating systems when it comes to adding and removing modules as well as virtual host configuration. The differences are the result of an effort to make it more flexible and […]

Drive Parity

Parity is a function of RAID in which an XOR result of at least two striped blocks is calculated and stored on an additional block. This requires at least three drives. Two of the drives will contain striped block data, the remaining drive will contain a parity block. How parity works Assume we have three […]

Drive Mirroring

Mirroring is a function of RAID in which data stored on one drive is duplicated on another drive. This creates redundant identical copies of data. There must be two physical drives in a set. Because data is duplicated to both drives, there is no gain in write speeds. Advantages to Mirroring With mirroring, if one […]

Drive Striping

Striping is a function in RAID that distributes data across multiple physical drives. Data can be striped at a bit or block level. Block sizes of data typically range between 4 and 128 KB blocks. Many systems default to 64KB blocks. Determine the best stripe size You will first need to determine the average file […]

Installing Apache in Ubuntu

Apache is currently the most commonly used and trusted web server application. It has dominated as the primary web server software. In this lesson we will learn to install the application as well as setup firewall rules to allow it server web pages to clients. Installing Apache Before we install Apache, it will be a […]

Software RAID

The term “software RAID” refers to using an operating system to accomplish RAID. The operating system makes the RAID volume available during the boot up process. Most of the well known operating systems provide software to accomplish RAID. In Windows operating systems you can create a RAID array using the Disk Management tool. This applies […]