Backups

Backups

• backing up data to protect against data loss by creating copies that can be restored.

• Three types

  • Full

  • Differential

  • Incremental

Full Backups

• backups all files every time

• level 0 backup

Differential Backups

• backs up files that have been changed or added since the last FULL backup

• easier to restore than incremental

• level 1 backup

Incremental Backups

• backs up files that have been changed or added since the last backup of any kind

• most difficult to restore

• level 2 backup

Custom Backups

• enables the configuration of backups differently for each volume

Individual server-based backup

• fastest for indiv servers

• requires a separate backup drive in each server

Centralized Backup

• allows multiple servers and worksatops to be backed up using a single backup server

Individual Drives Backups

• commonly placed in each server and used for indiv server backups

Media Libraries Backup

• containts at least one drive mechanism and multiple media units

• library can swap media using a robotic arm

Magnetic Tape

• most common type of media

• slow r/w transfer rates

• sequential instead of random access

Optical Storage

• typically faster than magnetic tape

• random access

• fewer libraries available

Media Rotation

• media is rotated so no single set is always in use

• Methods:

  • Simple

  • GFS

Simple Media Rotation

• weekly full backups, followed by a daily incremental

• requires one media set for each day

GFS Media Rotation

• grandfather, father, son

• differential backups daily, followed by one full backup each week

• previous weekly full backup is promoted to monthly backup