arangodump Examples

arangodump can be invoked in a command line by executing the following command:

  1. 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:

  1. arangodump --output-directory "dump" --overwrite true

arangodump will by default connect to the _system database using the default endpoint. To override the endpoint, or specify a different user, use one of the following startup options:

  • --server.endpoint <string>: endpoint to connect to
  • --server.username <string>: username
  • --server.password <string>: password to use (omit this and you’ll be prompted for the password)
  • --server.authentication <bool>: whether or not to use authentication

If you want to connect to a different database or dump all databases you can additionally use the following startup options:

  • --all-databases true: must have access to all databases, and not specify a database.
  • --server.database <string>: name of the database to connect to

Note that the specified user must have access to the databases.

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

  1. arangodump --server.endpoint tcp://192.168.173.13:8531 --server.username backup --server.database mydb --output-directory "dump"

In contrast to the above call --server.database must not be specified when dumping all databases using --all-databases true:

  1. arangodump --server.endpoint tcp://192.168.173.13:8531 --server.username backup --all-databases true --output-directory "dump-multiple"

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

  1. 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 <bool>: set to true to include documents in the dump. Set to false to exclude documents. The default value is true.
  • --include-system-collections <bool>: whether or not to include system collections in the dump. The default value is false. Set to true if you are using named graphs that you are interested in restoring.

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

  1. 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:

  1. arangodump --collection myusers --collection myvalues --output-directory "dump"

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

Cluster Backup

Starting with Version 2.1 of ArangoDB, the arangodump tool also supports sharding and can be used to backup data from a Cluster. Simply point it to one of the Coordinators and it will behave exactly as described above, working on sharded collections in the Cluster.

Please see the Limitations.

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.

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 referenced collection or arangodump yields an error.

  1. arangodump --collection clonedCollection --output-directory "dump"
  3. 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. Dump the prototype collection as well:

  1. arangodump --collection clonedCollection --collection prototypeCollection --output-directory "dump"
  3. Processed 2 collection(s), wrote 81920 byte(s) into datafiles, sent 1 batch(es)

Or override that behavior to be able to dump the collection in isolation individually:

  1. arangodump --collection clonedCollection --output-directory "dump" --ignore-distribute-shards-like-errors
  3. Processed 1 collection(s), wrote 34217 byte(s) into datafiles, sent 1 batch(es)

Note that in consequence, restoring such a collection without its prototype is affected. See documentation on arangorestore for more details about restoring the collection.

Encryption

Dump encryption is only available in the Enterprise Edition, including ArangoDB Oasis.

Starting from version 3.3 encryption of the dump is supported.

The dump is encrypted using an encryption keyfile, which must contain exactly 32 bytes of data (required by the AES block cipher).

The keyfile can be created by an external program, or, on Linux, by using a command like the following:

  1. dd if=/dev/random bs=1 count=32 of=yourSecretKeyFile

For security reasons, it is best to create these keys offline (away from your database servers) and directly store them in your secret management tool.

In order to create an encrypted backup, add the --encryption.keyfile option when invoking arangodump, in addition to any other option you are already using. The following example assumes that your secret key is stored in ~/SECRET-KEY:

  1. arangodump --collection "secret-collection" dump --encryption.keyfile ~/SECRET-KEY

Note that arangodump will not store the key anywhere. It is the responsibility of the user to find a safe place for the key. However, arangodump will store the used encryption method in a file named ENCRYPTION in the dump directory. That way arangorestore can later find out whether it is dealing with an encrypted dump or not.

Trying to restore the encrypted dump without specifying the key will fail:

  1. arangorestore --collection "secret-collection" dump --create-collection true

and arangorestore will report the following error:

  1. the dump data seems to be encrypted with aes-256-ctr, but no key information was specified to decrypt the dump
  2. it is recommended to specify either `--encryption.keyfile` or `--encryption.key-generator` when invoking arangorestore with an encrypted dump

It is required to use the exact same key when restoring the data. Again this is done by providing the --encryption.keyfile parameter:

  1. arangorestore --collection "secret-collection" dump --create-collection true --encryption.keyfile ~/SECRET-KEY

Using a different key will lead to the backup being non-recoverable.

Note that encrypted backups can be used together with the already existing RocksDB encryption-at-rest feature.

Compression

Introduced in: v3.4.6

--compress-output

Data can optionally be dumped in a compressed format to save space on disk. The --compress-output option can not be used together with Encryption.

If compression is enabled, no .data.json files are written. Instead, the collection data gets compressed using the Gzip algorithm and for each collection a .data.json.gz file is written. Metadata files such as .structure.json and .view.json do not get compressed.

  1. arangodump --output-directory "dump" --compress-output

Compressed dumps can be restored with arangorestore, which automatically detects whether the data is compressed or not based on the file extension.

  1. arangorestore --input-directory "dump"

Dump output format

Introduced in: v3.8.0

Since its inception, arangodump wrapped each dumped document into an extra JSON envelope, such as follows:

  1. {"type":2300,"key":"test","data":{"_key":"test","_rev":..., ...}}

This original dump format was useful when there was the MMFiles storage engine, which could use different type values in its datafiles. However, the RocksDB storage engine only uses "type":2300 (document) when dumping data, so the JSON wrapper provides no further benefit except compatibility with older versions of ArangoDB.

In case a dump taken with v3.8.0 or higher is known to never be used in older ArangoDB versions, the JSON envelopes can be turned off. The startup option --envelope controls this. The option defaults to true, meaning dumped documents will be wrapped in envelopes, which makes new dumps compatible with older versions of ArangoDB.

If that is not needed, the --envelope option can be set to false. In this case, the dump files will only contain the raw documents, without any envelopes around them:

  1. {"_key":"test","_rev":..., ...}

Disabling the envelopes can reduce dump sizes a lot, especially if documents are small on average and the relative cost of the envelopes is high. Omitting the envelopes can also help to save a bit on memory usage and bandwidth for building up the dump results and sending them over the wire.

As a bonus, turning off the envelopes turns arangodump into a fast, concurrent JSONL exporter for one or multiple collections:

  1. arangodump --collection "collection" --threads 8 --envelope false --compress-output false dump

The JSONL format is also supported by arangoimport natively.

Dumps created with the --envelope false setting cannot be restored into any ArangoDB versions older than v3.8.0!

Threads

Since v3.4.0, arangodump can use multiple threads for dumping database data in parallel. To speed up the dump of a database with multiple collections, it is often beneficial to increase the number of arangodump threads. The number of threads can be controlled via the --threads option, which defaults to 2.

arangodump versions prior to v3.8.0 distribute dump jobs for individual collections to concurrent worker threads, which is optimal for dumping many collections of approximately the same size, but does not help for dumping few large collections or few large collections with many shards.

Since v3.8.0, arangodump can also dispatch dump jobs for individual shards of each collection, allowing higher parallelism if there are many shards to dump but only few collections. Keep in mind that even when concurrently dumping the data from multiple shards of the same collection in parallel, the individual shards’ results will still be written into a single result file for the collection. With a massive number of concurrent dump threads, some contention on that shared file should be expected. Also note that when dumping the data of multiple shards from the same collection, each thread’s results will be written to the result file in a non-deterministic order. This should not be a problem when restoring such dump, as arangorestore does not assume any order of input.