system.md

MongoDB system

Dump

Single database

mongodump --authenticationDatabase admin -u admin -p password --port 17017 --db db_name --gzip --archive=db_name.gz

All databases

for db_name in $(echo 'show dbs' |  mongo --port 17017 | grep -v -E 'admin|config|local' | grep B$ | cut -d' ' -f 1); do
  mongodump --authenticationDatabase admin -u admin -p password --port 17017 --db ${db_name} --gzip --archive=${db_name}.gz
done

Restore

Single database

cat db_name.gz | mongorestore --drop --authenticationDatabase admin -u admin -p password --port 17017 --gzip --archive

All databases

password=password
for db_name in $(echo * | sed 's/.gz//g'); do
  cat ${db_name}.gz | mongorestore --drop --authenticationDatabase admin -u admin -p ${password} --port 17017 --gzip --archive
done

Dump pipe to restore

mongodump --host <source_host>:<port> --db <database_name> --gzip --archive | \
mongorestore --drop -vvvvvv -h <target_host>:<port> --db <database_name> --gzip --archive```

## Compact collections

Compact (to recover unused disk space) all collections in a single database:

db.getCollectionNames().forEach(function (collectionName) { print('Compacting: ' + collectionName); db.runCommand({ compact: collectionName }); });

### Check, increase and compact oplog size

use local db.oplog.rs.stats().maxSize

db.adminCommand({replSetResizeOplog: 1, size: Double(16000)})

db.runCommand({ "compact" : "oplog.rs" } )