RLEC 4.0.0-49 Release Notes (June 18, 2015)

If you are upgrading from a previous version, make sure to review the upgrade instructions before running through the upgrade process.

In addition, when running the install.sh script to upgrade the software, you might be prompted to approve changes to a configuration file named ccs-redis.conf. It is crucial that you choose Yes when asked whether to update this file.

New features

  • Support for Red Hat Enterprise Linux (RHEL) and CentOS 6.5 and 7 operating systems.
  • Support for additional AWS AMIs for Ubuntu and Amazon Linux, on multiple AWS regions.
  • Support for additional browsers and operating systems for the management UI.
  • Replica Of feature which enables creating a Redis database that keeps synchronizing data from another Redis database.
  • Rack-zone awareness feature which enables mapping nodes to racks/zones to ensure a more sophisticated high-availability mechanism.
  • Database-related alerts and email alerts.
  • Auto-configuration of synchronization of cluster server clocks with NTP as part of installation script.
  • Database Export functionality.
  • Email alerts on database Export and Import.


  • Database Backup Now functionality replaced with Export functionality.
  • Database performance improvements to increase throughput and reduce latency.
  • Improvement to AOF rewrite mechanism to deal with extreme-write scenarios and limited disk space configurations.
  • Enhancements to rladmin CLI to support additional commands.

Fixed issues

  • Cluster stability improvements related to removing nodes and taking nodes offline.
  • rladmin CLI bug fixes.

Known issues

  • Issue: RLEC-6819 - Uninstall on Red Hat Enterprise Linux does not stop all services and if you try to install the software again on the same machine the new installation might use prior installation data.

    Workaround: Before installing the software again restart the machine or verify that all services are down.

  • Issue: In the replica of process, if the source database is resharded while the replica of process is active, the synchronization process will fail.

    Workaround: You need to manually stop and restart the synchronization process after resharding of the source database is done.

  • Issue: In the replica of process, high database traffic might cause the replica of process to restart frequently as result of the "replica buffer" being exceeded. In this case you see the status of the replica of process as "Syncing" frequently.

    Workaround: You need to manually reconfigure the "replica buffer" through rladmin and set the buffer size to a new size. In order to find the appropriate buffer size please contact support at: support@redislabs.com.

  • Issue: In a cluster that is configured to support rack-zone awareness, if the user forces migration of a master or replica shard, through rladmin, to a node on the same rack-zone as its corresponding master or replica shard, and later runs the rebalance process, the rebalance process will not migrate the shards to ensure rack-zone awareness compliance.

    Workaround: In the scenario described above, you need to manually migrate the shard, through rladmin, to a node on a valid rack-zone in order to ensure rack-zone awareness compliance.

  • Issue: In case you deploy a cluster and use the DNS option for the cluster name (see details in How to set the Cluster Name (FQDN), do not configure the DNS entries for the cluster nodes, and try to configure a database that is a replica of another database within the cluster, then the UI allows you to configure the source database but the replica of process fails in runtime.

    Workaround: The configuration indicated in this issue is not a valid cluster configuration. If you choose to use the DNS option for the cluster name then you must configure DNS entries for the nodes, otherwise the cluster does not operate correctly. You have to either update the DNS accordingly, or recreate the cluster and use the mDNS option for the cluster name as described in How to set the Cluster Name (FQDN).

  • Issue: When taking a node offline or removing a node, if the node being taken offline or removed is currently serving as the web server for the web browser being used to view the management UI, then the management UI appears down while the node is down.

    Workaround: If you are using the cluster name in order to connect to the management UI in the browser, and the cluster name is registered in your external DNS or you are using the mDNS option, then the DNS entries will be updated to point to another node in the cluster after a few seconds and the UI will open properly. If you are not using the cluster name but rather the node IP in order to connect to the management UI in the web browser, you have to use the IP of another node in the cluster to access the management UI.

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