RLEC 4.2.1-30 Release Notes (October 18, 2015)

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

New features

  • rsyslog logging support - RLEC now writes by default to syslog, which enables monitoring through rsyslog.
  • Profile support for tuning cloud and non-cloud environments -- enables the administrator to configure RLEC to run with different performance profiles that are optimized for either cloud or non-cloud environments. For additional details, refer to the Performance optimization section.
  • SLA for AOF rewrite - enables the administrator to configure database parameters, by running the rladmin tune command, related to when AOF rewrite is triggered based on the time it would take to load the database from the AOF file, and on the maximum AOF rewrite file size. In addition, updates to the AOF rewrite mechanism minimize chances of the disk getting full.
  • New warning and alerts related to AOF rewrite mechanism - a warning is shown during the setup process in case the disk size is lower than twice the size of the RAM. New cluster level alerts added to alert when node available disk space is lower than the needed disk space for AOF rewrite purposes, and when node performance is degraded due to reaching disk I/O limits.
  • Replica Of support for multiple sources - the Replica Of feature is enhanced to support creating a database that is a replica of multiple source databases. For additional details, refer to the Replica Of section.
  • Cross cluster Replica Of - the Replica Of feature now supports defining a database that is a replica of databases that belong to a different RLEC cluster. For additional details, refer to the Replica Of section.
  • Multi-IP support - on a node that has multiple IPs, enables the administrator to specify which IP address is used for internal traffic and which IP addresses are used for external traffic. For additional details, refer to Multi-IP & IPv6 support.
  • IPv6 support for external traffic - on a node that has multiple IPs, external IP addresses can be of IPv6 type. For additional details, refer to Multi-IP & IPv6 support section.
  • Support for OpenStack Object Store ("Swift") location for import / export / backup. For additional details, refer to Database backup and Importing data to a database sections.
  • Import of a sharded database - support for importing data of a sharded database by indicating multiple files paths. For additional details, refer to the Importing data to a database section.
  • Enable running the install script in silent mode using "-y" parameter for default answers ("Y") or "-c" for file path parameters for custom answers. For additional details, refer to Accessing and installing the setup package section.
  • New rladmin command-line-interface "info" command allows for fetching current value of tunable parameters.


  • rladmin command-line-interface can only be run under user root or redislabs. For additional details, refer to the rladmin command-line interface (CLI) section.
  • Import / export / backup to/from Amazon S3 requires supplying the credentials per usage instance; it does not use central cloud credentials that used to be supplied in the Settings -> General page.
  • Fields related to storing Amazon S3 Cloud credentials have been removed from Settings -> General page.
  • Performance optimization in the database resharding mechanism.
  • Persistent and ephemeral storage cluster level alerts are enabled by default and set to 70%.
  • Various enhancements to rladmin command-line-interface (CLI) to support new commands.
  • Redis version updated to 2.8.21 that addresses CVE-2015-4335/DSA-3279 - Redis Lua Sandbox Escape.
  • Port 3336 added to the list of ports being used by RLEC.
  • Node "Network utilization" alert measured in percentages (%) has been updated to "Network throughput" alert measured in MBps. If the alert was defined then it will be disabled when upgrading to this version and the user needs to reconfigure it with a new value.
  • Performance improvements to the database Import to make the process much faster.
  • Enhancements to the support package to include additional details.
  • Removed support for SSL 2.0/3.0 protocols due to security vulnerabilities.
  • Disabled "dofile" functionality in Redis to solve a possible security vulnerability.
  • rladmin CLI "tune watchdog profile" command syntax updated to "tune cluster watchdog_profile".

Fixed issues

  • Support for relative path for backup and import functionalities.
  • Fix issue with TLS configuration of email server settings.
  • Email alerts not sent for database export and import processes.
  • Fix erroneous entries in the Log page.
  • Sometimes a wrong value is reported in the UI for node used ephemeral storage space.
  • Sometime the wrong Replica Of Lag value is reported in the UI.
  • RLEC-6875 - email server settings not working when using port 587.
  • RLEC-5498 - Improve rladmin response time when a node is down.
  • Validation of Replica Of source definition did not fail in the UI and would only fail in runtime if it was using the Cluster Name (FQDN) and the FQDN was not properly configured in the DNS.
  • Various improvements to error messages reported by rladmin.

Known issues

  • Issue: Connecting from a client to a database endpoint with mixed upper case and lower case letters can result in a slow response from the database.

    Workaround: The cluster name (FQDN) should consist of only lower-case letters. When connecting from a client to a database endpoint, only lower case letters should be used in the endpoint.

  • Issue: When upgrading a node to a new RLEC version (refer to Upgrading nodes while the node is in the offline state (refer to Taking a node offline, the upgrade process succeeds but might result in an unstable cluster.

    Workaround: Do not try to upgrade a node while it is in the offline state.

  • Issue: In Red Hat Enterprise Linux, and CentOS operating systems, the process used for cleaning up internal log files does not work, thereby allowing the log files to grow and possibly result in disk space issues.

    Workaround: On each machine that functions as a node in the cluster, create a file named "redislabs", and save it in the following location: "/etc/logrotate.d/" (e.g. "/etc/logrotate.d/redislabs"). The file should contain the following text:

    /var/opt/redislabs/log/\*.log {
    rotate 7

    The file's permissions should be root:root, 644. Afterwards, from the operating system command line interface (CLI) run the following commands:

    yum install policycoreutils-python
    semanage fcontext -a -t var_log_t '/var/opt/redislabs/log(/.\*)?'
    restsorecon -R /var/opt/redislabs/log
  • Issue: In the Replica Of process, if the target database does not have replication enabled and it is restarted or fails for any reason, the data on target database might not be in sync with the source database, although the status of the Replica Of process indicates it is.

    Workaround: You need to manually stop and restart the synchronization process in order to ensure the databases are in sync.

  • 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 restart the Replica of process 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.

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