Technical White Paper Dell EMC Fault Resilient Memory This technical white paper briefs about the Dell EMC’s Fault Resilient Memory (FRM) operating mode. This document covers the behavioral aspects of FRM on yx4x PowerEdge servers and later generation servers with VMware ESXi. Abstract This technical white paper briefs about Fault Resilient Memory (FRM) mode on VMware ESXi, and the Reliable Memory (ReM) technology enabled from VMware ESXi, which uses the resilient region exposed by the platform.
Revisions Revisions Date Description December 2013 Initial release November 2019 Updated Acknowledgements This paper was produced by the following: Author: Krishnaprasad K, Principal Engineering Technologist Support: Ramya D R, Technical Writer, IDD team Others: Mukund Khatri, Sandeep J The information in this publication is provided “as is.” Dell Inc.
Table of contents Table of contents Revisions.............................................................................................................................................................................2 Acknowledgements .............................................................................................................................................................2 Table of contents .................................................................................................
Executive summary Executive summary This technical white paper elaborates on the behavioral aspects of Fault Resilient Memory operating mode on Dell EMC’s yx4x PowerEdge servers and later. This document briefs about the command line options and VMware documentation which helps the administrators to know the memory reserved for reliable region, map the memory address range used by userworld and virtual machines to the reliable memory region.
Introduction to Dell Fault Resilient Memory (FRM) 1 Introduction to Dell Fault Resilient Memory (FRM) Fault Resilient Memory (FRM) is an operating mode introduced from yx2x PowerEdge servers. The mode establishes an area of memory that is fault resilient and can be used by hypervisors such as VMware ESXi to load vmkernel, critical applications or services to maximize system availability etc.
Introduction to Dell Fault Resilient Memory (FRM) 1.4 Behavioral description of FRM on yx4x PowerEdge servers and later On the yx4x PowerEdge server, only FRM operating mode is supported. Overall 25 percentage of system memory is reserved for reliable memory region. The 25 percentage of the total system memory populated on the server is reserved for reliable region. The 75 percentage of the total system memory populated is available for the end user applications for general purpose use. • • 1.
Introduction to Dell Fault Resilient Memory (FRM) The below screenshot is taken from a Dell EMC PowerEdge R840 indicating the BIOS token to enable FRM in server BIOS. Figure 1 1.6 : Enabling FRM Memory Operating Mode in the BIOS Verifying ReM from VMware ESXi VMware ESXi 5.5 and later versions enables Reliable Memory (ReM) by default (for supported versions Enterprise, Enterprise Plus). The user does not have to make any configuration changes in ESXi to enable ReM.
Introduction to Dell Fault Resilient Memory (FRM) Figure 3 :Listing ESXi ReM kernel parameter Commands such as esxtop and esxcli hardware memory get help the user to understand the memory reserved for fault resiliency, when this option is enabled from sever BIOS. The below screenshot is an output when you run the command Esxtop, and then press m. This output shows the memory specific attributes.
Introduction to Dell Fault Resilient Memory (FRM) 1.8 Configure Reliable memory for Virtual Machines VMware define a priority mechanism for various processes running on ESXi to ensure that the reliable memory region is mapped to processes based on their priority. VMKernel and the VMM gets the highest priority (Priority 0) and they make use of the reliable memory region when it is enabled from the platform.
FAQs 2 FAQ 1. What are the Dell server models that support FRM? - For more information, see your respective server’s Installation and Service Manual available at www.dell.com/support. See the Memory Settings section to know if your server supports FRM. 2. Does FRM require any specific DIMM population configurations and what are the configurations? - Yes, FRM requires specific DIMM population configuration. For more information.
Summary 3 Summary This white paper details both Dell EMC’s Fault Resilient Memory mode and VMware’s Reliable Memory technology. It explains about the feature, the prerequisites required to enable the reliable memory and the steps needed to enable FRM from the PowerEdge server BIOS. The paper also provides some of the command line utilities to monitor the size reserved for reliable region, and documentation on marking virtual machine’s memory to the reliable region etc.
References 4 References • • • 12 What’s New in the VMware vSphere 6.
