5 seconds does seem very fast, but this is on a high-end Rackspace server with what I'm sure are very fast hard drives and some 64GB of RAM. It's a bit slower o

5 seconds does seem very fast, but this is on a high-end Rackspace server with what I'm sure are very fast hard drives and some 64GB of RAM. It's a bit slower on "normal" boxes, but still quite quick. You can still write to your database, yes. There's a flag, --oplog, which when passed to mongodump, will record the oplog position at the time the backup starts, then dump any ops since the backup started as a part of the backup, so they get replayed on restore. This leaves your data consistent with the database state at the end of the backup without the need to issue a write lock.