MongoDB: Database replication

Db.copydatabase ("from", "to", "127.0.0.1:16161");

The From library on the 127.0.0.1. Copy to the to library.

There is an added benefit to doing so. This is the library in the From library that may have deleted the data. Look, we know that disk space is not freed when data is deleted. Refer to another article in the blog: MongoDB Delete the collection after the disk space is not released

Ken can cause a lot of disk space to occupy. Although the data can be repaired with db.repairdatabase (). But there are two bad places in this approach. 1. Operation on production if an unexpected stop can result in a risk of data unrecoverable. 2. If the disk space is low, less than the current DB time occupied space, this situation is not used db.repairdatabase ().

So we introduce the method of using Db.copydatabase to back up the data.

1.db.copydatabase ("from", "to", "127.0.0.1:16161"), copy a new to database. This is already the smallest data footprint. The data file of the to is generated in the database directory.

2. Change the configuration of all programs from the from library to the to library. The test is correct.

3. You can delete the from library at this point. Method. Use from after Db.dropdatabase (). The advantage of this method is that you can delete the data on the disk in time. Save a lot of space.

MongoDB: Database replication