Data migration plan
A hospital, HIS system hardware upgrade, the original Oracle database is running on the Win2000 server, and now you have the system to transfer the system to the newly purchased server, and the HIS system can tolerate downtime at 6 o'clock in the evening. The HIS system must remain normally.
Since the customer's local situation is not clear, we now come to a different environment to simply describe the system migration scheme.
One: Cold Backup
System conditions: The new legacy system database version is the same, the file system does not change
Basic work: Normally shut down the database, then in the cold backup of the database. Back up all Data file, control file, redo file, parameter file, then copy the cold backup to the new server, then create a new same name instance (Instance) on the new server, then you can run the backup data file from the new open Open .
Disadvantages: Require downtime for several hours, the main time is on the copy file.
Advantages: Because it is a cold-backup, there is no data consistency, and the environment where the recovered database is completely exactly the same as the original system (which avoids some changes in the SQL execution plan), the system is small, in case Failure old system can continue to run.
Two: EXP / IMP
System conditions: The new legacy system database version can be different, can be migrated across platforms
Basic Work: EXP is performed on the new system, and it is best to put the user database as readonly before the expiration starts at the beginning, then perform some IMP on the new database (if the database version is different, exp / IMP should pay attention to the version and character sets.).
Disadvantages: EXP / IMP may be a comparison with a large amount of data (dozens of g)
Slow (specific time should be specific to specific tests), the database is in Readonly, and only the query service can be provided.
Advantages: EXP / IMP can be upgraded across platforms across platforms, and system risk is small.
Three: Hot Backup
Since the system is allowed to stop, the recovery is complex, not recommended.
The above scheme If the database version is the same, the first method of using the first method is the best. The specific backup time can consult the hospital's system administrator. Individuals believe that the first method can be accomplished in 8 hours, the second method is The second method is used in the case where the system database version is changed.
