Mastering MongoDB 4.x - Second Edition

Backing up by copying raw files

If we don't want to use any of the preceding options that were outlined, our last resort is to copy the raw files using cp/rsync, or something equivalent. This is generally not recommended, for the following reasons:

• We need to stop all of the writes before copying files
• The backup size will be larger, since we need to copy indexes and any underlying padding and fragmentation storage overhead
• We cannot get point-in-time recovery by using this method for replica sets, and copying data from sharded clusters in a consistent and predictable manner is extremely difficult

Making a backup by copying raw files should be avoided, unless no other option really exists.