To avoid any data loss, you can make backups of one or all the sharded Solr indexes.
Trigger a backup with an HTTP command which instructs the
/replication handler to backup the Solr shards, for
example:
curl http://solrshard20xbm.alfresco.com:9000/solr4/<CORE_NAME>/replication?command=backup \&location=/mnt/solrContentStoreBackup\&numberToKeep=1
where:
<CORE_NAME> specifies the name of the core you are working with.
location specifies the path where the backup will be created. If the path is not absolute then the backup path will be relative to Solr's instance directory.
numberToKeep specifies the number of backups to keep.
Backup status
The backup operation can be monitored to see if it has completed by sending the
details command to the /replication handler, for
example:
http://solrshard20xbm.alfresco.com:9000/solr4/<CORE_NAME>/replication?command=details