HDFS Transparency limitations and recommendations

This topic lists the limitations and recommendations for CES HDFS.

• In IBM Storage Scale 5.0.4.2, the installation toolkit does not support the ESS deployment for CES HDFS. For efix support, send an email to scale@us.ibm.com or upgrade to IBM Storage Scale 5.0.4.3 or later with the correct BDA integration toolkit HDFS Transparency support matrix.
• Red Hat® Enterprise Linux® is supported.
• CES HDFS supports installation of HDFS Transparency 3.1.1/3.2.2/3.3.0.
• Upgrade path from HDFS Transparency 3.1.0 and earlier to CES HDFS Transparency 3.1.1 is not supported.
• Upgrade path from HDFS Transparency 3.1.1 and earlier to CES HDFS Transparency 3.2.2 is not supported.
• Upgrade path from HDFS Transparency 3.2.2 and earlier to CES HDFS Transparency 3.3.0 is not supported.
• In IBM Storage Scale 5.0.4.2, remote mount setup is not supported through the installation toolkit. From IBM Storage Scale 5.0.4.3, remote mount setup is supported with the correct BDA integration toolkit HDFS Transparency support matrix.
• Ambari is not supported for CES HDFS integration.
• CES only monitors and does failover for HDFS Transparency NameNodes.
• ZKFailoverController is not used for CES HDFS HA.
• It is required to setup a CES shared root file system (cesSharedRoot) for storing CES shared configuration data, for protocol recovery and for other protocol specific purposes.
• In general, to install and configure CES, all protocols packages available on your platform must be installed. Installing a subset of available protocols is not supported.

  However, CES HDFS protocol is an exception. HDFS will only be installed if it is enabled.

• The mmuserauth is not used by CES HDFS. Manual Kerberos configuration is required to configure Hadoop services.
• The mmhadoopctl command is for HDFS Transparency 3.1.0 and earlier. Do not use mmhadoopctl in the CES HDFS environment.
• Do not use the mmhdfs start/stop/restart command on the NameNodes. Instead use the mmces service start/stop hdfs command to start and stop the NameNodes.
• For generic HDFS Transparency Hadoop distribution support information, see Hadoop distribution support.
• The mmhdfs import/export/upload/config set commands are based on the HDFS Transparency configuration directory: /var/mmfs/hadoop/etc/hadoop.
• The file system ACL setting for -k nfs4 is not supported for the Hadoop environment. Set the file system ACL -k value to all. For more information, see Hadoop ACL and IBM Storage Scale protocols and Issues that can be encountered if the IBM Storage Scale ACL is not set properly.
• CES HDFS does not support viewfs.
• CES HDFS does not support hdfs crypto -listZones. For a workaround with the GPFS policy engine, see the step 31 in the Second generation HDFS Transparency Protocol troubleshooting topic.
• CES HDFS does not support short-circuit mode.
• For remote mount limitation information, see Limitations of protocols on remotely mounted file systems in IBM Storage Scale: Administration Guide.
• For IBM Storage Scale software and scaling limitations, see Software questions and Scaling questions in IBM Storage Scale FAQ.
• For additional recommendations and restrictions, see CES HDFS Planning.