Downgrading

A direct, in-place downgrade of ArangoDB is not supported. If you have upgraded your ArangoDB package, and then also upgraded your current data directory, it is not supported to downgrade the package and start an older ArangoDB version on a data directory that was upgraded already.

If you are using a standalone ArangoDB server, data directory could have been upgraded automatically during package upgrade. If you are using the Starter to start your ArangoDB, and you have not triggered yet the rolling upgrade, or upgraded it manually, your data directory is (probably) still on the old version, so you should be able to downgrade the binaries in this case.

Supported downgrade procedures

In order to downgrade, the following options are available:

• Restore a backup you took using the tool arangodump before the upgrade.
• Start the old package on the data directory backup you took before the upgrade.

Restore an arangodump backup

This procedure assumes that you have taken an arangodump backup using the old ArangoDB version, before you upgraded it.

1. Stop ArangoDB (if you use a Cluster, stop all the needed processes on all the machines).
2. As extra precaution, take a backup of your current data directory (at filesystem level). If you use a Cluster, you will need to backup all the data directories of all the processes involved, from all machines. Make sure you move your data directory backup to a safe place.
3. Uninstall the ArangoDB package (use appropriate purge option so your current data directory is deleted, if you are using a stand alone instance).
4. Install the old version of ArangoDB.
5. Start ArangoDB. If you are using the Starter, please make sure you use a new data directory for the Starter.
6. Restore the arangodump backup taken before upgrading.

Start the old package on the data directory backup

This procedure assumes that you have created a copy of your data directory (after having stopped the ArangoDB process running on it) before the upgrade. If you run a Cluster, this procedure assumes that you have stopped them before the upgrade, and that you have taken a copy of their data directories, from all involved machines.

This procedure cannot be used if you have done a rolling upgrade of your Cluster setups because in this case you do not have a copy of the data directories.

1. Stop ArangoDB (if you use a Cluster, stop all the needed processes on all the machines).
2. As extra precaution, take a backup of your data directory (at filesystem level). If you use a Cluster, you will need to backup all the data directories of all the processes involved, from all machines. Make sure you move your backup to a safe place.
3. Uninstall the ArangoDB package (use appropriate purge option so your current data directory is deleted, if you are using a stand alone instance).
4. Install the old version of ArangoDB.
5. Start ArangoDB on the data directory that you have backup-ed up (at filesystem level) before the upgrade. As an extra precaution, please first take a new copy of this directory and move it to a safe place.

Other possibilities

If you have upgraded by mistake, and:

• your data directory has been upgraded already
• it is not possible for you to follow any of the Supported Downgrade Procedures because:
  • you do not have a dump backup taken using the old ArangoDB version
  • you do not have a copy of your data directory taken after stopping the old ArangoDB process and before the upgrade

One possible option to downgrade could be to export the data from the new ArangoDB version using the tool arangoexport and reimport it using the tool arangoimport in the old version (after having installed and started it on a clean data directory). This method will require some manual work to recreate the structure of your collections and your indexes - but it might still help you solving an otherwise challenging situation.