DRS Advanced option "MaxHostMemOvercommitPct" for Maximum percentage of memory overcommitment allowed per host

Products

• VMware vCenter Server

Issue/Introduction

• This Advanced option(MaxHostMemOvercommitPct) is used for DRS Resource management.
• It makes limitation of memory overcommitment.
• If you set this value to '0' then it disables the memory overcommitment for DRS.
• This option value is not calculated by host physical memory but available resource which is not included kernel + user reserved memory. So it should be considerd.
• You can check the available memory using below command on ESXi host SSH session.

memstats -r group-stats -T -l2 -s gid:name:min:conResv:availResv:memSize -u mb 2> /dev/null | sed -n '/^-\+/,/.*\n/p'
---------------------------------------------------------------------------------
     gid   name                              min    conResv  availResv    memSize
---------------------------------------------------------------------------------
       0   host                           130563       9455     121108      13572
       1   system                           4391       4375     121124       4243
       2   vim                                 0       4872     121108        793
       3   iofilters                           0         40     121108         27
       4   user                                0        154     121108       8511
---------------------------------------------------------------------------------
conResv : consumed reservation
AvailResv : available reservation

From the result, 121108(host availResv) + 154(User conResv) value(in MB) could be available memory.

Environment

vSphere 7.x
vSphere 8.x

Resolution

To set the DRS advanced option perform the following steps from the vSphere client:
1. Right-click the DRS cluster and click Settings > vSphere DRS > Edit > Advanced Options > Add
2. In the Option column enter:
MaxHostMemOvercommitPct
3. Click in the Value column to enter the desired value in Pct, then click OK for this setting to take effect.