Storage Systems and Methods Quiz

Storage

• Storage is any medium data can be written to and retrieved from
• Long-term storage includes flash drives, SD cards, CDs and DVDs, magnetic tape, SSDs and HDDs

Server Storage

• Server storage is based on HDDs
• SSDs are gaining popularity
• SSDs use flash memory and high-speed interfaces
• SATA is the common interface for SSDs
• SSDs have no moving parts, require less power, faster, more resistant to shock but less capacity than HDDs

Reasons for Storage

• We need storage for OS files, log files, virtual machines, database storage, user documents and more

Storage Access Methods

• Storage access methods include local storage, DAS, NAS and SAN

Local Storage

• Storage media with a direct exclusive connection to a computer's system board, through a disk controller
• Usually inside the computer's case, usually refers to HDDs and SSDs
• Disadvantage: only the system where it's installed has direct access

Direct-Attached Storage

• Similar to local storage but can also refer to one or more HDDs in an enclosure with its own power supply

Network-Attached Storage

• Enclosure, power supply, slots for multiple HDDs, a network interface and a built-in OS
• Typically dedicated to file sharing
• Shares files through SMB, NFS, FTP

Storage Area Network

• Uses high-speed networking technologies to give servers fast access to large amounts of shared disk storage
• Fibre Channel and iSCSI are common network technologies used in SANS

Configuring Local Disks

• Disk configuration can be divided into physical disk properites and logical disk properties
• Physical disk properties include disk capacity, physical speed and disk interface
• Logical disk properties include disk format and partitions or volumes
• A disk drive can contain one or more volumes
• A partition is an older term that means the same thing as a volume
• Formatting prepares a disk with a file system used to organize and store files

Disk Capacity and Speed

• HDD capacities are now measured in hundreds of gigabytes
• One and two TB disks are common
• Factors affecting HDD speed: disk interface technology and rotation speed
• Servers should have an HDD with a minimum speed of 7200rpm
• 10,000-15,000rpm is preferred

Disk Capacity Considerations

• Windows installation should be on a separate disk from data
• SSD is a good choice for Windows installation

Disk Interface Technologies

• Disk interface connects a disk to a computer system, usually with a cable
• The faster the bus, the faster the system can read and write to the disk
• The most common types of disk interfaces are SATA, SAS and SCSI

Serial ATA

• Drives have mostly replaced PATA drives
• Advantages: faster transfer times and smaller cable size
• SATA drives are inexpensive, fast and reliable
• The current standard supports speeds up to 16Gb/s

Small Computer System Interface

• A parallel bus technology still used on some servers but has reached its performance limits
• The latest variation is Ultra-640 which supports up to 640 MB/s transfer rates

Serial Attached SCSI

• A newer serial form of SCSI with transfer rates up to 6GB/s and higher
• SATA drives can be connected to SAS backplanes
• Backplane is a connection system that uses a printed circuit board to carry signals