Using and Configuring Storage Devices

Storage

Any digital medium that data can be written to and later retrieved.

Computer Storage

Generally means long-term storage in which data is maintained without a power source.

Non-Volatile Storage (NVM)

Long-term storage, such as hard disks and flash drives, maintains data when the power is turned off and is referred to as

Examples of Long-term storage

• USB memory sticks (flash drives)

• Secure Digital (SD) cards and Compact Flash (CF) cards

• CDs and DVDs

• Magnetic tape

• Solid-state drives

• Hard disk drives

Reasons for Storage

1. Operating System Files

2. User Applications

3. User Documents

4. Virtual Memory

5. Log Files

6. Virtual Machines

7. Database Storage

File size of OS in Window

3 to 8 GB

File size of OS in Linux

• Ubuntu: Approximately 4 GB or more for the installation ISO.

• Fedora: Around 2 to 4 GB for the installation ISO.

• Debian: About 3 to 5 GB, depending on the version and whether you choose a minimal or full install.

• Arch Linux: The ISO is around 800 MB, but it’s a minimal install, so additional space is needed for packages.

• Linux Mint: Approximately 2 to 3 GB for the installation ISO.

File size of OS in macOS

• Installation files for macOS range from about 12 to 16 GB.

• Once installed, most operating systems typically require around 10 to 20 GB of disk space, though this can vary based on the packages and applications you choose to install.

User Applications

Often use the most storage space, especially if users run entire office suites and multimedia applications like photo editing programs.

User documents

Take up the most space if pictures, videos, and audio files are being stored on the computer.

Disk Quotas

it is used in servers that store user files so that a single user can’t monopolize the disk space.

Virtual Memory

• Most OSs use virtual memory to supplement physical RAM.

• Virtual memory is disk space that is used to store the least recently used pages of memory when more physical RAM is needed but not available.

• In Windows, virtual memory is stored as a file called pagefile.sys, which is usually located at the root of the C: drive.

• In Linux OSs, virtual memory is implemented as a swap partition, a separate partition on the disk set aside exclusively for virtual memory.

Log Files

• Most OSs maintain log files to which various system components and applications can write when an event occurs.

• Log files can be used to track down system or security problems.

• Log files can slowly eat up disk space unless you keep an eye on their size and delete or archive them periodically.

Virtual Machines

• If a server is a virtualization server, you need plenty of space to store files for virtual hard disks.

• Because it is so widely used, virtualization is one of the largest uses of disk space on servers.

Database Storage

• If a server is running one or more databases, disk storage requirements vary depending on the size of the databases.

• Because databases can grow dynamically, it’s a good idea to store them on a drive separate from the drive where the OS is installed, preferably on a volume that can have its capacity expanded if needed.

Storage Access Methods

There are four broad categories of storage access methods:

1. Local storage

2. Direct-Attached Storage (DAS)

3. Network-attached storage (NAS)

4. Storage Area Network (SAN)

Local Storage

• storage media with a direct, exclusive connection to the computer’s system board through a disk controller.

• The term local storage usually refers to HDDs or SSDs instead of DVDs or other types of media.

• The downside of local storage is that only the system where it’s installed has direct access to the storage medium.

Direct-Attached Storage (DAS)

• It is similar to local storage in that it’s connected directly to the server using it.

• DAS can also refer to one or more HDDs in an enclosure with its own power supply.

Network-attached storage (NAS)

• Sometimes referred to as a storage appliance, has an enclosure, a power supply, slots for multiple HDDs, a network interface, and a built-in OS tailored for managing shared storage.

• NAS is designed to make access to shared files easy to set up and easy for users to access.

Storage Area Network (SAN)

• The most complex type of storage which uses high-speed networking technologies to give servers fast access to large amounts of shared disk storage.

• use the concept of a logical unit number (LUN) to identify a unit of storage.

• A LUN is a logical reference point to a unit of storage that could refer to an entire array of disks, a single disk, or just part of a disk.

Configuring Local Storage

Two Categories:

1. Physical disk properties

2. Logical Properties

Physical disk Properties

capacity, speed, and interface

Logical Properties

format, partition, and volume

Disk Interface Technologies

• The disk interface connects a disk to a computer system, usually with some type of cable.

• The cable acts as a bus that carries data and commands between the disk and the computer.

Types of disk interface

1. Serial ATA drives

2. SCSI and SAS drives

   SAS – Serial Attached SCSI

3. Non-Volatile Memory express

Serial ATA drives

Have replaced parallel ATA (PATA) drives and have several advantages over this older technology, including faster transfer times and smaller cable sizes.

Small computer system interface (SCSI) and SAS drives

Have been a mainstay in enterprise-class servers for decades, and this drive technology has endured through more than a half dozen upgrades.

Non-volatile memory express (NVMe)

is a storage interface and protocol for SSDs, and it uses the PCIe bus directly.

Types of Volumes

1. Simple Volume

2. Spanned Volume

3. RAID 0 Volume

4. RAID 1 Volume

5. RAID 5 Volume

Simple Volume

Resides on a single disk. Simple volumes can be extended (made larger) using the OS’s disk utilities if unallocated space is available on the disk.

Spanned Volume

Extends across two or more physical disks.

RAID 0 Volume

Extends across two or more disks, but data is written to all disks in the volume equally.

RAID 1 Volume

• Mirrored Volume

• Uses space from two disks and provides fault tolerance. Data written to one disk is duplicated, or mirrored, to the second disk.

RAID 5 Volume

• disk stripe with parity

• Uses space from three or more disks and uses disk striping with parity to provide fault tolerance.

Two volumes in Windows:

1. boot volume

2. system volume

Boot Volume

The volume where the \Windows folder is located. The usual location is the C drive, but this is not mandatory. It is also called the boot partition.

System Volume

Contains files that the computer needs to find and load the Windows OS. In Windows 2008 and later versions, it’s created automatically during installation if you’re installing an OS for the first time on the system.