Solr Backup and Restore

Backup

Solr has its own pre-backup script:

The script iterates over all cores, and for every core:

  • Remove previous dump.

  • Create snapshot.

  • Dump snapshot.

  • List snapshots.

  • Delete all snapshots that have been created by this pre-backup script.

Notes:

  • The pre-backup script is configured and integrated into BURP by profile_solr.

  • Solr supports dumping a core without creating a snapshot, but tests in practice have shown that this doesn’t work reliably; dumps can fail non-deterministically, probably due to concurrent updates.

  • The dump status of Solr is poorly implemented. In particular if the dump produced an exception, the dump status won’t tell WHICH dump failed, hence the pre-backup script might report an error even if the CURRENT dump actually succeeded. Re-running the pre-backup script MAY eventually resolve this situation.

Restore

List available backups using BURP:

$ sudo burp -a L -r '/var/lib/solr-backup/snapshot.solr-pre-backup.<core>'

Restore dump to /tmp/:

$ sudo burp -a r -b <backup_number> -r '/var/lib/burp-backup/snapshot.solr-pre-backup.<core>' -d /tmp
# creates /tmp/var/lib/solr-backup/snapshot.solr-pre-backup.<core>.<date>.<time> with all the core's data

Finally, the core must be re-imported into Solr:

$ curl
http://localhost:8983/solr/<core_to>/replication?command=restore&location=%2ftmp%2fvar%2flib%2fsolr-backup%2f&name=solr-pre-backup.<core_backup>.<date>.<time_encoded>

Note:

  • You can restore any <core_backup> to any existing (but empty) <core_to>

  • location may need to be adjusted if you restored the files somewhere other than /tmp (escape the slashes as %2f)

  • time_encoded: Encode the ':' as '%3A'

  • The 'snapshot.' prefix must be removed

  • If your Solr is set up to use TLS, you probably need --insecure

  • If your Solr is set up to use authentication, you probably need --basic -u '<user>:<password>'

You can now monitor the progress of the restore:

$ curl http://localhost:8983/solr/<core_to>/replication?command=restorestatus

Note:

  • The responseHeader.exception field will contain an exception if something went wrong

    • Check the permissions of the restored files; if required, fix them, for example using

      $ chown -R solr:solr /tmp/var/lib/solr-backup

  • The responseHeader.status field will either say "In Progress" and finally "success" if everything is well.

  • If your Solr is set up to use TLS, you probably need --insecure

  • If your Solr is set up to use authentication, you probably need --basic -u '<user>:<password>'