arangodump Examples

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

arangodump --output-directory "dump"

This connects to an ArangoDB server and dump all non-system collections from the default database (_system) into an output directory named dump. Invoking arangodump fails 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:

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

arangodump connects to the _system database by default 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:

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:

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

When finished, arangodump prints 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)

Also, more than one endpoint can be provided, such as:

arangodump \
  --server.endpoint tcp://192.168.173.13:8531 \
  --server.endpoint tcp://192.168.173.13:8532 \
  --server.username backup \
  --all-databases true \
  --output-directory "dump-multiple"

By default, arangodump dumps 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:

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

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

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

Structural information for a collection is saved in files with name pattern <collection-name>.structure.json. Each structure file contains a JSON object with these attributes:

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

Document data for a collection is 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

The arangodump tool supports sharding and can be used to backup data from a Cluster. Simply point it to one of the Coordinators and it behaves exactly as described above, working on sharded collections in the Cluster.

Please see the Limitations.

As above, the output is 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.

Dumping collections with sharding prototypes

Collections may be created with the shard distribution identical to an existing prototypical collection (see distributeShardsLike); 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.

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

ERROR [f7ff5] {dump} An error occurred: Collection clonedCollection's shard distribution is based on that of collection prototypeCollection, which is not dumped along.

You need to dump the prototype collection as well:

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

...
INFO [66c0e] {dump} Processed 2 collection(s) from 1 database(s) in 0.132990 s total time. Wrote 0 bytes into datafiles, sent 6 batch(es) in total.

Encryption

ArangoDB Enterprise Edition ArangoGraph

You can encrypt dumps 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:

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:

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

Note that arangodump does not store the key anywhere. It is the responsibility of the user to find a safe place for the key. However, arangodump stores 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 fails and arangorestore reports an error:

arangorestore --collection "secret-collection" dump --create-collection true
...
the dump data seems to be encrypted with aes-256-ctr, but no key information was specified to decrypt the dump
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:

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

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

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

Compression

--compress-output

Data can optionally be dumped in a compressed format to save space on disk. The --compress-output option cannot 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.

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.

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:

{"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 are 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 only contain the raw documents, without any envelopes around them:

{"_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:

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

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. The default value was changed from 2 to the maximum of 2 and the number of available CPU cores.

The --threads option works dynamically, its value depends on the number of available CPU cores. If the amount of available CPU cores is less than 3, a threads value of 2 is used. Otherwise the value of threads is set to the number of available CPU cores.

For example:

  • If a system has 8 cores, then max(2,8) = 8, i.e. 8 threads are used.
  • If it has 1 core, then max(2,1) = 2, i.e. 2 threads are used.

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 are still 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 are 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.

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