Dumping Data from an ArangoDB database

To dump data from an ArangoDB server instance, you will need to invoke arangodump. Dumps can be re-imported with arangorestore. arangodump can be invoked by executing the following command:

unix> arangodump --output-directory "dump"

This will connect to an ArangoDB server and dump all non-system collections from the default database (_system) into an output directory named dump. Invoking arangodump will fail if the output directory already exists. This is an intentional security measure to prevent you from accidentally overwriting already dumped data. If you are positive that you want to overwrite data in the output directory, you can use the parameter --overwrite true to confirm this:

unix> arangodump --output-directory "dump" --overwrite true

arangodump will by default connect to the _system database using the default endpoint. If you want to connect to a different database or a different endpoint, or use authentication, you can use the following command-line options:

  • --server.database : name of the database to connect to
  • --server.endpoint : endpoint to connect to
  • --server.username : username
  • --server.password : password to use (omit this and you'll be prompted for the password)
  • --server.authentication : whether or not to use authentication

Here's an example of dumping data from a non-standard endpoint, using a dedicated database name:

unix> arangodump --server.endpoint tcp:// --server.username backup --server.database mydb --output-directory "dump"

When finished, arangodump will print out a summary line with some aggregate statistics about what it did, e.g.:

Processed 43 collection(s), wrote 408173500 byte(s) into datafiles, sent 88 batch(es)

By default, arangodump will dump both structural information and documents from all non-system collections. To adjust this, there are the following command-line arguments:

  • --dump-data : set to true to include documents in the dump. Set to false to exclude documents. The default value is true.
  • --include-system-collections : whether or not to include system collections in the dump. The default value is false.

For example, to only dump structural information of all collections (including system collections), use:

unix> arangodump --dump-data false --include-system-collections true --output-directory "dump"

To restrict the dump to just specific collections, there is is the --collection option. It can be specified multiple times if required:

unix> arangodump --collection myusers --collection myvalues --output-directory "dump"

Structural information for a collection will be saved in files with name pattern .structure.json. Each structure file will contains a JSON object with these attributes:

  • parameters: contains the collection properties
  • indexes: contains the collection indexes

Document data for a collection will be saved in files with name pattern .data.json. Each line in a data file is a document insertion/update or deletion marker, alongside with some meta data.

Starting with Version 2.1 of ArangoDB, the arangodump tool also supports sharding. Simply point it to one of the coordinators and it will behave exactly as described above, working on sharded collections in the cluster.

However, as opposed to the single instance situation, this operation does not guarantee to dump a consistent snapshot if write operations happen during the dump operation. It is therefore recommended not to perform any data-modifcation operations on the cluster whilst arangodump is running.

As above, the output will be one structure description file and one data file per sharded collection. Note that the data in the data file is sorted first by shards and within each shard by ascending timestamp. The structural information of the collection contains the number of shards and the shard keys.

Note that the version of the arangodump client tool needs to match the version of the ArangoDB server it connects to. By default, arangodump will produce a dump that can be restored with the arangorestore tool of the same version. An exception is arangodump in 3.0, which supports dumping data in a format compatible with ArangoDB 2.8. In order to produce a 2.8-compatible dump with a 3.0 ArangoDB, please specify the option --compat28 true when invoking arangodump.

unix> arangodump --compat28 true --collection myvalues --output-directory "dump"

Advanced cluster options

Starting with version 3.1.17, collections may be created with shard distribution identical to an existing prototypical collection; i.e. shards are distributed in the very same pattern as in the prototype collection. Such collections cannot be dumped without the reference collection or arangodump with yield an error.

unix> arangodump --collection clonedCollection --output-directory "dump"

ERROR Collection clonedCollection's shard distribution is based on a that of collection prototypeCollection, which is not dumped along. You may dump the collection regardless of the missing prototype collection by using the --ignore-distribute-shards-like-errors parameter.

There are two ways to approach that problem: Solve it, i.e. dump the prototype collection along:

unix> arangodump --collection clonedCollection --collection prototypeCollection --output-directory "dump"

Processed 2 collection(s), wrote 81920 byte(s) into datafiles, sent 1 batch(es)

Or override that behaviour to be able to dump the collection individually.

unix> arangodump --collection B clonedCollection --output-directory "dump" --ignore-distribute-shards-like-errors

Processed 1 collection(s), wrote 34217 byte(s) into datafiles, sent 1 batch(es)

No that in consequence, restoring such a collection without its prototype is affected. arangorestore