The esxcfg-advcfg command is interesting as there is not a huge amount of help about this command. However, we can figure out that it is meant to do advanced configuration and we can figure out some settings that can be made. The -g switch is used to “get” settings; the -s switch is used to “set” settings.Here are a few examples of some VMkernel parameters which can be interrogated.[root@esx1host vmware]# esxcfg-advcfg -g /Misc/BlueScreenTimeoutValue of BlueScreenTimeout is 0

[root@esx1host vmware]# esxcfg-advcfg -g /Misc/HostName

Value of HostName is esx1.vmlab.net

The question is, how much is configurable? To figure out what is configurable, we recommend that you look in the directory /proc/vmware/config which you will find in the service console command line and then you will see the following directories

BufferCache

Cpu

Disk

FileSystem

Irq

LVM

Mem

Migrate

Misc

Net

NFS

Numa

Scsi

User

VMFS3

From these directories and the files within, you can work out the paths to be supplied to the esxcfg-advcfg command as parameters. Alternatively, you could also use the command

esxcfg-info -o

to list the advanced options.

We often see this tool used to make configuration changes relating to storage. For example, below, you can see we are checking to see if we are creating virtual disks in “eager zero” format by default, whether we will discover non-contiguous numbered LUNs, the maximum LUN number addressed,the SCSI conflict retry count and finally the logical volume manager (LVM) setting for resignaturing VMFS volumes.

[root@esx1host vmware]# esxcfg-advcfg -g /VMFS3/ZeroedThickVirtualDisks

Value of ZeroedThickVirtualDisks is 1

[root@esx1host vmware]# esxcfg-advcfg -g /Disk/SupportSparseLUN

Value of SupportSparseLUN is 1

[root@esx1host vmware]# esxcfg-advcfg -g /Disk/MaxLUN

Value of MaxLUN is 255

[root@esx1host vmware]# esxcfg-advcfg -g /Scsi/ConflictRetries

Value of ConflictRetries is

[root@esx1host vmware]# esxcfg-advcfg -g /LVM/EnableResignature

Value of EnableResignature is

In this last example, we are again setting a parameter related to storage. This parameter limits the number of outstanding disk request for each VM. This is intended to equalise the disk access between virtual machines.

[root@esx1host vmware]# esxcfg-advcfg -s 16 /Disk/SchedNumReqOutstanding

When using the esxcfg-advcfg command, remember case sensitivity!

Usage: esxcfg-advcfg <options> [<adv cfg Path>]

-g|–get Get the value of the config option

-s|–set <value> Set the value of the config option

-d|–default Reset Config option to default

-q|–quiet Suppress output

-k|–set-kernel Set a VMkernel load time option value.

-j|–get-kernel Get a VMkernel load time option value.

-h|–help Show this message.

-r|–restore Restore all advanced options from the configuration file. (FOR INTERNAL USE ONLY).