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Backing Up Oracle - Computing at Cornell

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Incremental backup of control files or archived logs is not supported. There<br />

are two types of incremental backups: non-cumul<strong>at</strong>ive and cumul<strong>at</strong>ive.<br />

10.2.3.1 Non-cumul<strong>at</strong>ive incremental backup<br />

A non-cumul<strong>at</strong>ive incremental backup backs up only those blocks th<strong>at</strong> have<br />

changed since the previous incremental backup <strong>at</strong> the same or lower level.<br />

This is the default mode of oper<strong>at</strong>ion for incremental backups.<br />

A level 0 backup backs up all blocks th<strong>at</strong> contain d<strong>at</strong>a. It performs the same<br />

backup as a full backup. A level 0 backup is required for subsequent<br />

incremental backups <strong>at</strong> other levels. An incremental backup <strong>at</strong> a level gre<strong>at</strong>er<br />

than level 0 backs up only those blocks th<strong>at</strong> have changed since a previous<br />

incremental backup <strong>at</strong> the same or lower level. The size of the backup<br />

depends on the number of blocks modified.<br />

Figure 48 illustr<strong>at</strong>es part of a monthly cycle of non-cumul<strong>at</strong>ive incremental<br />

backups. The cycle is based on backup levels 0, 1, and 2. A weekly backup is<br />

performed <strong>at</strong> level 0 on Sunday, incremental backups level 2 are performed<br />

on Monday to Wednesday and on Friday and S<strong>at</strong>urday, and weekly<br />

incremental backups <strong>at</strong> level 1 on each Thursday.<br />

Figure 48. Differential incremental backups<br />

10.2.3.2 Cumul<strong>at</strong>ive incremental backup<br />

A cumul<strong>at</strong>ive incremental backup <strong>at</strong> level n contains only blocks th<strong>at</strong> have<br />

been changed since the most recent backup <strong>at</strong> level n - 1 or lower.<br />

Chapter 10. <strong>Oracle</strong> backup consider<strong>at</strong>ions on Windows 2000 161

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