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  1. Introduction
  2. Network Model
  3. Topology
  4. Physical Media
  5. Wireless Media
  6. Network Card
  7. Modems
  8. Outside Connections
  9. Wide Area Network Connections
  10. Repeaters, Bridges, Routers
  11. Network Types
  12. Ethernet
  13. Token Ring
  14. ARCnet
  15. AppleTalk
  16. FDDI
  17. Architecture Comparisons
  18. Categories
  19. TCP/IP
  20. IPX/SPX
  21. NetBEUI
  22. AppleTalk
  23. SNA
  24. Others
  25. Suites and Network Layers
  26. Installing Drivers
  27. DNS
  28. Network Operating Systems
  29. Applications, mail, groupware, DBMS
  30. Backing up the network
  31. Troubleshooting
  32. Web, SNMP, admin, firewalls
  33. Networking Terms and Definitions
  34. Credits

Backing up the Network

Items to do when considering network backups.

  • Set a backup schedule.
  • Determine data to be backed up and its importance to determine a backup schedule.
  • Determine backup methods, media, and equipment to use. Backup methods include full backup, file copy, backup changed files without marking files as backed up (differential backup), or backup only the files that have changed since the last backup and mark them as backed up (incremental backup).
  • Determine where to store backup information such as a safe.
  • Test the backup and restore capability of the backup system and its media to be sure it really works.
  • Maintain backup logs.

Redundant Array of Inexpensive disks (RAID)

RAID is a fault tolerant method of storing data, meaning that a failure can occur and the system will still function. The various RAID categories are:

  • 0 - Disk striping - Data is written across multiple drives in parallel. Different parts of the data is written at the same time to more than one drive. If there are two drives, half the data is written to one drive, while the rest of the data is written to the other drive. All partitions on striped drives must be the same size. No fault tolerance is provided with RAID-0.
  • 1 - Disk mirroring - All the data is written to two drives so each drive has a complete of all stored data. If one drive fails, the other can be used to get a copy of the data. To be more fault tolerant, more than one controller card may be used to control the mirrored hard drives. This is called disk duplexing and will allow the system to keep functioning if one controller card fails.
  • 2 - Disk striping with error correction codes (ECC).
  • 3 - Disk striping with ECC parity information stored on a separate drive.
  • 4 - Disk striping with blocks with parity information stored on a separate drive.
  • 5 - Disk striping with blocks with parity information stored using multiple drives. Uses five disks with one fifth of each one to store parity information.

Sector Sparing

Sector sparing will detect when data is going to be read from or written to a bad sector on the hard drive and will move the data to a good sector. The bad sector is marked as not available so it is not used again.

Windows NT support

Supports RAID-0,1, and 5 along with sector sparing.


  • DAT - Digital Audio Tape.
  • Sector Sparing - A method of fault tolerance that automatically identifies and marks bad sectors as not available. It is also called hot-fixing.
  • SLED - Single Large Inexpensive disk - The concept that a large disk costs less per amount of storage than several smaller ones. Somehow this concept is used as a means of fault tolerance.