If the size of your available core dump partition is insufficient, you can configure ESXi to use a file on a VMFS datastore for diagnostic information.

Note: VMFS datastores on software iSCSI do not support core dump files.

Prerequisites

Install ESXCLI. See Getting Started with ESXCLI. For troubleshooting, run esxcli commands in the ESXi Shell.

Procedure

  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
    --auto | -a Automatically create a file if none found.
    --datastore | -d datastore_UUID or datastore_name Specify the datastore for the dump file. If not provided, the system selects a datastore of sufficient size.
    --enable | -e Enable the diagnostic file after creation.
    --file | -f file_name Specify the file name of the dump file. If not provided, the system creates a unique name for the file.
    --size |-s file_size_MB Set the size in MB of the dump file. 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
    --enable |-e Enable or disable the dump file. This option cannot be specified when unconfiguring the dump file.
    --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

    --unconfigure | -u Unconfigure the current VMFS dump file.
  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

What to do next

For information about other commands you can use to manage the core dump files, see the ESXCLI Reference documentation.