Generating a VMkernel zdump manually from a dump file in ESXi host

Products

• VMware vSphere ESXi

Issue/Introduction

When extracting a VMkernel core and the associated diagnostic files, a bundle is generated also known as VMkernel zdump. This article provides information on generating a VMkernel zdump from a pre-configured dump file.

 

For more information on generating a VMkernel zdump from a diagnostic partition, see Extracting a core dump file from the VMKCore diagnostic partition following a purple diagnostic screen error (343591).

The process for dumping VMkernel cores after a host fails and placing the dump into a file is introduced in ESXi 5.5.

 

For more information on how to configure a core dump file, see Configuring ESXi coredump to file instead of partition (314320).

Environment

VMware vSphere ESXi 7.0
VMware vSphere ESXi 8.0
VMware vSphere ESXi 6.7

Resolution

The command line utility for generating a VMkernel zdump is:

esxcfg-dumppart
 

Different options are available depending on the configuration and location of the dump files, and location for placing the zdump file.

 

Generating the VMkernel zdump from the current active dump file to the default location: /scratch/core

Note: These steps are not recommended if the /scratch partition is not configured on persistent storage as you may run out of space. For more information on scratch location, see Creating a persistent scratch location for ESXi 4.x and 5.x (317689).

 

1. Log in to the ESXi host using the SSH. 
2. Run this command to restore the current dump file configuration and ensure that the dump file is configured and activated:
   
   esxcli system coredump file get
   
   For example:
   
   # esxcli system coredump file get
   Active: /vmfs/volumes/527d1d8f-########-####-##########ab/vmkdump/564DDB42-####-####-####-##########AB.dumpfile
   Configured: /vmfs/volumes/527d1d8f-########-####-##########ab/vmkdump/564DDB42-####-####-####-##########AB.dumpfile
    
3. Run this command to generate the VMkernel zdump:
   
   esxcfg-dumppart --file --copy --devname active
   
   The path to the output file is displayed so that you can locate the zdump.
   
   For example:
   
   # esxcfg-dumppart --file --copy --devname active
   Created file /scratch/core/vmkernel-zdump.1

Generating the VMkernel zdump from the current active dump file to a specific location

1. Log in to the ESXi host using the SSH. 
2. Run this command to restore the current dump file configuration and ensure that the dump file is configured and activated:
   
   esxcli system coredump file get
   
   For example:
   
   # esxcli system coredump file get
   Active: /vmfs/volumes/527d1d8f-########-####-##########ab/vmkdump/564DDB42-####-####-####-##########AB.dumpfile
   Configured: /vmfs/volumes/527d1d8f-########-####-##########ab/vmkdump/564DDB42-####-####-####-##########AB.dumpfile
    
3. Run this command to generate the VMkernel zdump:
   
   esxcfg-dumppart --file --copy --devname active --zdumpname /vmfs/volumes/<datastore_name>/<output_filename>
    

   For example:
   
   # esxcfg-dumppart --file --copy --devname active --zdumpname /vmfs/volumes/datastore1/vmkernel-zdump
   Created file /vmfs/volumes/datastore1/vmkernel.zdump.1

Generating the VMkernel zdump from a specific dump file to a specific location

Note: Perform these steps to generate the VMkernel zdump file from the latest non-active dump file, if you have created and activated a new dump file after a previous host failure.

 

1. Log in to the ESXi host using the SSH. 
2. List all potential files matching the ESXi host dump files:
    
   For example:
    
   # esxcli system coredump file list
   Path Active Configured Size
   ------------------------------------------------------------------------------------------------------- ------ ---------- ---------
   /vmfs/volumes/527d1d8f-########-####-##########ab/vmkdump/564DDB42-####-####-####-##########AB.dumpfile true true 119537664
   /vmfs/volumes/527d1d8f-########-####-##########ab/vmkdump/manually_created_1.dumpfile false false 119537664
   /vmfs/volumes/527d1d8f-########-####-##########ab/vmkdump/manually_created_2.dumpfile false false 119537664
    
3. Generate the VMkernel zdump:
   
   esxcfg-dumppart --file --copy --devname /vmfs/volumes/file_location_from_step_2 --zdumpname /vmfs/volumes/datastore_name/output_filename
   
   For example:
   
   # esxcfg-dumppart --file --copy --devname /vmfs/volumes/527d1d8f-########-####-##########ab/vmkdump/test.dumpfile --zdumpname /vmfs/volumes/datastore1/vmkernel-zdump
   Created file /vmfs/volumes/datastore1/vmkernel-zdump.1
   esxcli system coredump file list