Configuring ESXi coredump to file instead of partition

Products

• VMware vSphere ESXi

Issue/Introduction

This article provides steps to configure ESXi to generate coredump as a file on VMFS.

 

On ESXi\ESX hosts that are upgraded to ESXi 5.5 and later, the core file size is limited to 100 MB. In most cases this is not enough to handle the coredump file size. VMware recommends to configure the ESXi host to generate coredumps as a file.

Note: ESXi 7.0 creates a VMFS-L based ESX-OSData volume and configures a coredump file to stored in it if the volume is larger than 4GB. If ESXi is installed to a USB/SDCard device, then the boot option allowCoreDumpOnUsb=TRUE will also need to be set before ESXi starts. A larger or alternative coredump file can be configured using the steps described in this article.

Environment

VMware vSphere ESXi 8.x
VMware vSphere ESXi 7.x
VMware vSphere ESXi 6.x

Resolution

Note: Software iSCSI and Software FCoE are not supported for coredump locations.

 

To configure ESXi to generate the coredump as a file on VMFS:

 

1. Create a VMFS datastore core dump file by running the following command:

esxcli system coredump file add

 

The command takes the following options, but they are not required and can be omitted:

Option	Description
--datastore | -d datastore_UUID or datastore_name	If not provided, the system selects a datastore of sufficient size. The Datastore can be a VMFS or VMFS-L volume.
--file | -f file_name	If not provided, the system specifies a unique name for the core dump file.
--size |-s file_size_MB	If not provided, the system creates a file of the size appropriate for the memory installed in the host.

2. Verify that the file has been created:

esxcli system coredump file list

 

You can see the output similar to the following:

 

Path                                             Active Configured Size

------------------------------------------------ ------ ---------- ---------

/vmfs/volumes/52b021c3-.../vmkdump/test.dumpfile false  false      104857600

3. Activate the core dump file for the host:

esxcli system coredump file set

 

The command takes the following options:

Option	Description
--path | -p	The path of the core dump file to use. The file must be pre-allocated.
--smart | -s	This flag can be used only with --enable | -e=true. It causes the file to be selected using the smart selection algorithm. For example, esxcli system coredump file set --smart --enable true

4. Verify that the core dump file is active and configured:

esxcli system coredump file list

 

The output similar to the following indicates that the core dump file is active and configured:

 

Path                                             Active Configured Size

------------------------------------------------ ------ ---------- ---------

/vmfs/volumes/52b021c3-.../vmkdump/test.dumpfile True   True       104857600

The output indicates that the active and configured status of the file is True.

Note: For more information on configuring the coredump file, see Creating a Diagnostic Partition.

Additional Information

Generating a VMkernel zdump manually from a dump file in ESXi host (2081902)