vSAN nodes experience LSOM Memory congestion due to high "Number of elements in commit tables" (vSAN 7.0 U3)

Products

• VMware vSAN 7.x

Issue/Introduction

This KB addresses LSOM memory congestion issues resulting in vSAN Memory congestion impacting builds prior to 7.0 Update 3 P06 (build: 20842708).

The symptoms and validation scripts in KB vSAN nodes experience LSOM Memory congestion due to high "Number of elements in commit tables" (vSAN 6.7 U3/vSAN 7.0 U1) are the same for this issue.

Environment

VMware vSAN 7.0.3

Cause

This issue is similar in cause and symptoms to the issue outlined in the related KB; however, it can still occur even if the following conditions are met:

• The esxcfg-advcfg setting value is already configured to the default of the later build.
• The workaround from the related KB (for example, setting /VSAN/ObjectScrubPersistMin to 0) has been applied.

This issue occurs in clusters where there are larger objects (which have a concatenated component layout) and is more likely to occur when these larger objects are IO-intensive.

 

Resolution

This issue is resolved in:

• ESXi 7.0 Update 3 P06 (build: 20842708)

Workaround:

The impacted Disk-Groups commit-table entries (and thus also the Memory congestion) can be cleared by unmounting and mounting the impacted Disk-Group.

If unmount and mount of the Disk-Groups via the vSphere UI or via CLI is not possible then rebooting the node with congested Disk-Group(s) will also automatically unmount and mount the Disk-Groups as part of node restart process, Maintenance Mode with Ensure Accessibility option may not be possible depending on the severity of the issue.