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Discussion in 'A+' started by spy22, May 20, 2008.

  1. spy22

    spy22 Byte Poster

    Hey all, could somebody please explain to me in very simple terms the differences between backups.

    Whenever i get a question i always seem to get differential in incremental mixed up somehow!?

    Many Thanks

    Certifications: Its who you know not what you know!!!
    WIP: CCNA?
  2. sunn

    sunn Gigabyte Poster

    So if we understand a full backup is a complete backup…
    An incremental backup is a backup of files that have been changed since the last backup (any backup not just full backup). The pros is very quick. The cons is it’s dependant on the previous incremental backups and full backup. Example: Day-1 full backup is done; Day-2 through Day-5 incremental backups are done. If on Day-6 a restore is needed, the procedure will involve the (tapes) starting with Full Backup and each incremental backup from Day-2 through Day-5 (in the correct order). This is cumbersome and if any of the backup media is corrupt you’ve got an incomplete restoration.

    A Differential Backup is *always* the difference from the last complete backup (full backup). So if on Day-1 a full backup is done; Day-2 a differential backup would be done. On Day-3 another differential backup is done and so on. Now if on Day-6 a restoration is required, only the full backup and the last differential backup (Day-5) is needed. Since the differential is a backup of everything since the last full backup, the backups between Day-2 and Day-4 are not needed. Pro is it’s pretty easy to restore, needing only 2 backups (Full and last Differential). Con is as each day that passes the differential gets bigger and thus may not be as quick as the incremental, and if not managed correctly it can become bigger than the original full backup.
  3. tripwire45
    Honorary Member

    tripwire45 Zettabyte Poster

  4. greenbrucelee
    Highly Decorated Member Award

    greenbrucelee Zettabyte Poster

    On the system I use at work we do a full back up once a month and incremental backups at the end of the week.
    Certifications: A+, N+, MCDST, Security+, 70-270
    WIP: 70-620 or 70-680?
  5. supernova

    supernova Gigabyte Poster

    This was my first IT job in 1999, I used to use full backup followed by several incremental backups as well. However, also had several tape sets and rotated them using the GFS (grandfather, father, son) method.

    Then several sets were kept off site and several in a fire safe on site.

    We had bespoke software to manage the tape sets and there drive cleaning, rotation, retention and lifespan.

    (I presume this is covered in the N+?)

    Certifications: Loads
    WIP: Lots

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