Backing up a collection from HDFS

You can back up Solr collections to your local cluster or a remote cluster using the solrctl utility to minimize data loss caused by accidental or malicious administrative actions. Learn how to create, prepare, and export the Solr collection snapshot to create a backup of the Solr collection.

If you are using a secure (Kerberos-enabled) cluster, specify your jaas.conf file by adding the following parameter to each command:

--jaas [***/PATH/TO/JAAS.CONF***]

If TLS is enabled for the Solr service, specify the truststore and password using the ZKCLI_JVM_FLAGS environment variable before you begin the procedure:

export ZKCLI_JVM_FLAGS="-Djavax.net.ssl.trustStore=[***/PATH/TO/TRUSTSTORE \
-Djavax.net.ssl.trustStorePassword=[***TRUST_STORE_PASSWORD***]"

Create a snapshot. On a host running Solr Server, run the following command:
```
solrctl collection --create-snapshot [***USER_DEFINED_NAME_OF_THE_SNAPSHOT***] -c [***NAME_OF_THE_COLLECTION_TO_BE_BACKED_UP***]
```
For example, for a collection named tweets the command:
```
solrctl collection --create-snapshot tweets-$(date +%Y%m%d%H%M) -c tweets
```
creates the snapshot tweets-202103281043.
If you are backing up the Solr collection to a remote cluster, prepare the snapshot for export. If you are backing up the Solr collection to the local cluster, skip this step.
```
solrctl collection --prepare-snapshot-export [***NAME_OF_THE_SNAPSHOT_TO_BE_EXPORTED***] -c [***COLLECTION_NAME***] -d [***DESTINATION_DIRECTORY***]
```
The destination HDFS directory path ([***DESTINATION_DIRECTORY***], specified by the -d option) must exist on the local cluster before you run this command. Make sure that the Solr superuser (solr by default) has permission to write to this directory.
For example:
```
hdfs dfs -mkdir -p /path/to/backup-staging/tweets-202103281043
hdfs dfs -chown :solr /path/to/backup-staging/tweets-202103281043
solrctl collection --prepare-snapshot-export tweets-202103281043 -c tweets \
-d /path/to/backup-staging/tweets-202103281043
```

Export the snapshot. This step uses the DistCp utility to back up the collection metadata as well as the corresponding index files. The destination directory must exist and be writable by the Solr superuser (solr by default).

To export the snapshot to a remote cluster, run the following command:

solrctl collection --export-snapshot [***NAME_OF_THE_SNAPSHOT_TO_BE_EXPORTED***] -s [***SOURCE_DIRECTORY***] -d [***PROTOCOL***]://[***NAMENODE***]:[***PORT***]/[***DESTINATION_DIRECTORY***]

For example:

HDFS
webHDFS

HDFS protocol:

solrctl collection --export-snapshot tweets-202103281043 -s /path/to/backup-staging/tweets-202103281043 \
-d hdfs://nn01.example.com:8020/path/to/backups

WebHDFS protocol:

solrctl collection --export-snapshot tweets-202103281043 -s /path/to/backup-staging/tweets-202103281043 \
-d webhdfs://nn01.example.com:20101/path/to/backups

To export the snapshot to the local cluster, run the following command:

solrctl collection --export-snapshot [***NAME_OF_THE_SNAPSHOT_TO_BE_EXPORTED***] -c [***COLLECTION_NAME***] -d [***DESTINATION_DIRECTORY***]

For example:

solrctl collection --export-snapshot tweets-202103281043 -c tweets -d /path/to/backups/

Delete the snapshot after exporting:

solrctl collection --delete-snapshot [***NAME_OF_THE_SNAPSHOT_TO_BE_DELETED***] -c [***COLLECTION_NAME***]

For example:

solrctl collection --delete-snapshot tweets-202103281043 -c tweets