Modification of congestion-related vSAN advanced parameters

Products

• VMware vSAN

Issue/Introduction

Modification of certain vSAN advanced configuration options can result in unexpected side effects.

Warning: VMware strongly advises against modification of any congestion-related advanced configuration parameters.

Environment

• VMware vSAN 6.x
• VMware vSAN 5.5.x

Resolution

VMware vSAN has a variety of advanced configuration parameters that modify how vSAN handles I/O requests, data management, data protection and various other aspects of the vSAN infrastructure. Although some advanced configuration parameters are generally useful, others can have profound implications on data integrity, reliability and availability.

VMware strongly advises against modification of any congestion-related advanced configuration parameters.
 

Note: It is not supported to adjust these values for normal production clusters or outside of specific guidance from Broadcom Support.

This includes, but is not limited to, the following options:

• /LSOM/lsomMemCongestionLowLimit
  • Default value: 75
     
• /LSOM/lsomMemCongestionHighLimit
  • Default value: 95
     
• /LSOM/lsomSsdCongestionLowLimit
  • Default value: 75
     
• /LSOM/lsomSsdCongestionHighLimit
  • Default value: 95
     
• /LSOM/lsomLogCongestionLowLimitGB
  • Default value: 16
     
• /LSOM/lsomLogCongestionHighLimitGB
  • Default value: 24

Although adjustments to these options are sometimes useful during troubleshooting or recovery, these options should remain unchanged (at their respective default values) unless adjustments are specifically recommended by Broadcom Support. Long-term changes to these values or misconfiguration of these values can result in data unavailability or data loss.