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In my case, I want to backup and restore all the databases. This might sound stupid but -

Instead of doing

# backup
mongodump  # takes time
# restore
mongorestore # takes a lot of time

Why can't I just

# backup
tar -cvzf /backup/mongo.tar.gz /data/db
# restore
tar -xzf /backup/mongo.tar.gz -C /data/db

Would this not work?

Optimus
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1 Answers1

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In principle, yes, that's possible, but there are several caveats. The strategies with their respective down- and upsides are discussed in detail in the backup documentation. Essentially, replica sets and sharding make the process more complex.

  • You'll have to shut down or lock the server so the files aren't being written to while you're copying them. Since copying still takes time, it makes sense to only do that on a secondary, otherwise your system will be effectively down.

  • Consider using file system / lvm snapshots (also discussed in the documentation); they are generally faster because the file system will do copy-on-write when necessary afterwards, so the actual snapshot takes only milliseconds. However, make sure you understand how that works on whatever LVM, file system or virtualization platform you're using, the performance characteristics can be peculiar, especially when keeping multiple snapshots.

  • Remember that any backup taken while the system is running is inconsistent - the only way to get a 'clean' backup is to gracefully shut down the application (so it finishes all pending writes but doesn't accept any further requests), then backup the database.

mnemosyn
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    It is only for a test setup on local machines, shutting down mongo is not an issue. Thanks for the documentation link, very helpful – Optimus Apr 18 '15 at 10:02