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Best Practices for Oracle 11g Backup and Recovery using RMAN and Dell EqualLogic Snapshots
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2 Oracle backup and recovery strategies overview
IT administrators can back up and recover an Oracle database using multiple methods, with each
method having its own advantages and disadvantages. The choice of method to use depends on
various factors, such as backup window requirements, recovery point, and recovery time objectives.
The EqualLogic volume snapshots feature used in conjunction with RMAN can help improve the
overall efficiency of backup and recovery operations. EqualLogic snapshots also provide the ability to
offload the RMAN backup copy operation to a dedicated backup processing server. This helps to
reduce the impact on precious production database server system resources during backup
processing.
Table 1 lists the most frequently used backup and recovery methodologies.
Table 1 – Oracle Backup and Recovery Methodologies
Methodology Description
Disk-to-Tape
Backup
The “classic” form of backup, in which the data is copied directly to tape
drives. Provides the most economical solution for archiving the data for
extended periods. Tape based backups are portable and a good choice for
off-site storage. However, there are performance implications since the
backup and recovery operations take significant time to complete.
Disk-to-Disk
Backup
One of the most common backup methods deployed today. Data is
copied directly between storage disks, thereby decreasing the
backup/recovery time significantly. In some cases a dedicated Virtual Tape
Library (VTL) is employed. In other cases the backup application writes to
disk in its own proprietary format. This solution has become more popular
because the cost per gigabyte of high capacity disks is decreasing.
However, disks are not easily portable like tapes and not suitable for long-
term archiving and off-site storage.
Disk-to-Disk-to-
Tape Backup
This method can provide the best of both worlds. Backups can be copied
to the disks regularly, and then moved to tape for long-term storage.
Using disks for regular backup helps decrease backup and recovery time
while the use of tape enables long-term data retention and offsite data
protection. This may involve using one or more backup utilities to manage
the entire process.
Database -
Complete
Recovery
This method recovers the database to the most recent state without
losing any committed transactions. This involves restoring the database to
the most recent good backup and then applying all the changes using
archived logs.
Database – Point-
in-Time Recovery
This scenario is more common than the full database recovery. This
happens typically when human errors occur (like deleting the contents of
a table) or database corruptions to the database. The database is returned
to its original state before the corruption occurred.