DataStores are a more efficient alternative to Blob storage. Additionally they provide for easier backup/restore. They only make sense when using
bundle persistence managers (org.apache.jackrabbit.core.persistence.bundle.
), as opposed to db ones (org.apache.jackrabbit.core.persistence.db.). DB PMs duplicate content in blobs, while bundle ones efficiently offload those to the datastore.
Jackrabbit 1.4.2 has issues with bundle PMs: e.g. see https://issues.apache.org/jira/browse/JCR-1499
https://issues.apache.org/jira/browse/JCR-1354
. Fix is available in Jackrabbit 1.4.3.