| Incremental Backup Strategy |
- Incremental Backups assume you have a "good" Full Backup
- one-day Incremental backups are worthless if yesterday's incremental failed
- Always do (multiple-day) spanning incremental backup starting from a full backup
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| Typical Daily Incrementals |
- When doing a typical Incremental Backup of just today's changes ( 1 day ),
if Tuesday's backup Fail, you will NOT be able to restore all files changed on Tue
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Normail daily (one-day) Incremental Backups |
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Tuesday's backup Failed |
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- Problem: Tuesday's changes are NOT backed up anywhere
- Problem: You will NOT be saving Tuesday's changes until your next full backup
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| Daily Span ==> Daily Incrementals Since Last Full Backup |
- Always backup starting from the last Full backup ( on Sunday )
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Sat |
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Sun - do 8-day spanning incremental (the past week)
Sun - do 32-day spanning Incremental Backup
Sun - do the Full Backup |
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Monday backups also include changes on Sunday |
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Tue and Wed daily incremental backups Fails
but is backed up on Thur |
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Thur span incremental backups will also backup Tue and Wed backups |
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Fri span incremental backups are from Sun thru Fri |
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Sat span incremental backups are from Sun thru Sat |
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- Incremental Backup SHOULD start (span) from a "full backup" until today
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| Weekly 32-day Span ==> Recreate Full Backups |
- Changes for the Last 32 days
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Sun |
Mon |
Tue |
Wed |
Thu |
Fri |
Sat |
Sun - do 8-day spanning incremental (the past week)
Sun - do 32-day spanning Incremental Backup
Sun - do the Full Backup |
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Sun |
Mon |
Tue |
Wed |
Thu |
Fri |
Sat |
Sun - Power Loss - No Full backup,
32-day Backup HAS TO BE working
otherwise, all backups is worthless for the week |
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Sun |
Mon |
Tue |
Wed |
Thu |
Fri |
Sat |
Sun - Bad 32-day Backup,
Full Backup HAS TO BE WORKING working
otherwise, all backups is worthless for the week |
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. . . v
. . . v
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Sun |
Mon |
Tue |
Wed |
Thu |
Fri |
Sat |
Back to normal incremental backups |
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- 32-Day Incremental Backup can be used to "recreate" a full backup
- Either the 32-Day Incremental or Full Backup must be functional
- You have a bad backup if BOTH full and 32-day incremental failed at the SAME time
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