Backup Process for Work Laptop Environment

My first quick & practical cycle of EA has led me to define the current state, goal state and gaps for the backup domain.  Now, I want to attempt documenting in greater detail the goal state for the backup process for my work laptop, and all this is still observing my goal of writing “just enough”.

I’ve installed O&O DiskImage (still considering if I should buy.  For now, I have 21 days left on my trial license).

Exclude Files

Using a software called WinDirStat, I can find large files hogging my computer.  I am excluding the following files from the imaging:

• \hiberfil.sys – included by default
• \pagefile.sys – included by default
• \System Volume Information\ – included by default
• Documents and Settings\<my user id>\
  • My Documents\Downloads – can download again
  • My Documents\My Pictures – separate backup strategy due to size
  • My Documents\My Music – separate backup strategy due to size
  • My Documents\My Dropbox – trial software
  • Temp copy from Seagate harddisk – temp storage
• Documents and Settings\All Users\Application Data\OO Software\DiskImage\Images\*.* – don’t want to backup the backups

Settings

• LZNT1 is preferred over Bzip2 for compression.  Bzip2 saves me 4Gb in disk space, but it took three hours instead of LZNT1’s one hour (36Gb)
• Store the image in my other work laptop
• Frequency – will try doing it monthly

Question

• How long should I keep a backup for?