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Home > Success Center > Log & Event Manager (LEM) > The Reason why LEM Needs Memory and CPU Resource Reservations

The Reason why LEM Needs Memory and CPU Resource Reservations

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Created by Tim Rush, last modified by Kevin.Kessler on Mar 24, 2017

Views: 208 Votes: 6 Revisions: 20

Overview

This write-up explains why LEM needs memory and CPU resources set in the form of reservations.

Environment

All versions of LEM

Detail

LEM requires resource reservations. LEM handles traffic in real-time—receiving and normalizing data, allowing rules to fire on the data, displaying data in the console, and pushing data into the database. A lot of the communication that makes this happen is Java based, and Java requires reservations.

 

Not all VM administrators know how LEM works but it is important to understand its processes. Justifying why the LEM needs reservations cannot be measured by looking at VM performance metrics. Because of what LEM does, memory and CPU reservations are critical to keeping the LEM running correctly. Certain functionality will not work without enough memory, and resource reservations prevent the VMware host and other VMs from stealing memory and CPU resources.

 

These links are essential to understanding LEM:

 

 

Additional Links:

  • Full memory reservation eliminates ballooning or hypervisor swapping leading to more predictable performance with no latency overheads due to such mechanisms.  For more information, click here. (© 2013 VMware, Inc., available at http://www.vmware.com/, obtained on May 4, 2016.)

  • Set the memory reservation value in the VMware Infrastructure Client to the size of memory for the virtual machine. To read more, click here.   (© 2013 VMware, Inc., available at http://www.vmware.com/, obtained on May 4, 2016.)

  • Without memory reservation, vSphere may reclaim memory from the VM, when the host free memory gets scarce. See more here. (© 2013 VMware, Inc., available at http://www.vmware.com/, obtained on May 4, 2016.)

  • If a performance-critical virtual machine needs a guaranteed memory allocation, the reservation needs to be specified carefully because it may impact other virtual machines. Visit "http://www.vmware.com/content/dam/di...management.pdf"  to read more. (© 2013 VMware, Inc., available at http://www.vmware.com/, obtained on May 4, 2016.)

 

Note: Using the VM performance metrics to define what is needed for the LEM will not help keep the LEM running. Without reservations, the virtual appliance will have stability issues and performance problems, and expect the LEM to go down periodically.

 

Disclaimer: Please note, any content posted herein is provided as a suggestion or recommendation to you for your internal use. This is not part of the SolarWinds software or documentation that you purchased from SolarWinds, and the information set forth herein may come from third parties. Your organization should internally review and assess to what extent, if any, such custom scripts or recommendations will be incorporated into your environment.  You elect to use third party content at your own risk, and you will be solely responsible for the incorporation of the same, if any.

 
Last modified
15:14, 24 Mar 2017

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