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HOW TO: FIX No coredump target has been configured. Host core dumps cannot be saved.

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Andrew Hancock (VMware vExpert PRO / EE Fellow/British Beekeeper)
EE Fellow, MVE, Expert of the Year 2021,2017-11, Scribe 2016-2012, Author of the Year 2018-6,2013-2012 VMware vExpert Pro, vExpert 2022-2011
This video builds on the last videos in this series of Hancock's VMware Half Hour, where we continue to build our VMware vSphere 7.0 Lab, and in this video, we start to explore the Warning messages appearing on several of our hosts in the cluster.

In this video, I will show you HOW TO: FIX the No coredump target has been configured. Host core dumps cannot be saved. There have been some changes in ESXi 7.0, and the core dumps can now only be written to SSD, HDD, NVMe, not persistent storage such as USB flash drives or SD cards. I discuss some of the issues with ESXi 7.0 and the support of USB flash drives and SD cards. There has been some confusion over the last 18 months about the support of ESXi 7.0 on USB flash drives and SD cards, VMware, Dell and HPE state there were not supported, because 7.0.2 or later caused issues with corruption of the ESXi installation if installed on these devices, and later VMware stated this was deprecated,. and then more recently did an about turn and not it's supported.

SD card/USB boot device revised guidance (85685)

I think the "writing is on the wall" and if you are in a production environment using USB flash drives and SD cards, now is the time to change to SSD, HDD, NVMe or SATADOM for ESXi installations.

The previous videos are listed here for your convenience

Part 5: HOW TO: Enable SSH Remote Access on a VMware vSphere Hypervisor 7.0 (ESXi 7.0).

Part 24: HOW TO: Cross vCenter Server vMotion (export) between standalone vCenter Servers 7.0 not linked to the current SSO domain.

Part 25: HOW TO: Add a Synology NAS providing NFS Storge to VMware vSphere Hypervisor ESXi 7.0.

Part 26: HOW TO: Create a VMware vSphere Cluster add an EVC Baseline and then present a Synology NAS to multiple hosts in the cluster.

Part 27: HOW TO: Migrate VMware vCenter Server 7.0 in an enabled EVC VMware vSphere 7.0 Cluster of ESXi 7.0 hosts using "Andy's Towers of Hanoi solution"

Part 28: HOW TO: FIX the Warning System logs on host are stored on non-persistent storage, Move system logs to NFS shared storage.

HOW TO: Suppress Configuration Issues System logs on host are stored on non-persistent storage

New Kernel options available on ESXi 7.0 (77009)

Configuring a diagnostic coredump partition on an ESXi host (2004299)

Video Steps

1. Connect to vCenter Server 7.0.

Using a web browser, enter the fully qualified domain name of the vCenter Server 7.0 in the URL.

2. Privacy Notice.

If using the VMware self-signed certificate (the default), click Accept to proceed.

3. Launch vSphere Client (HTML5).

Click the Launch vSphere Client (HTML5) button.

4. Enter SSO credentials.

Enter the Administrator@vsphere.local username and password.

5. Select the host.

Select the Host > Configuration > Advanced System Settings.

6. Enable core dump on USB/SD card - Search for variable.

allowCoreDumpOnUsb (hint it's on Page 41).

7. Change false to true.

Enter the word true.

8. Hit Enter to complete.

Hit Enter.

9. Enable SSH and Console Shell.

Select and enable SSH Secure Shell and ESXi Console.

10. SSH Connection.

Using the Windows application PuTTY or another SSH client, connect to the IP address of the ESXi host server, and enter the following commands

11. Search file systems.

esxcli storage file system list

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.

12. Record partition type VMFS-L.

Copy VMFS-L partition UUID.(hint it starts with LOCKER-

13. Create coredump file.

esxcli system coredump file add -d <UUID datastore> -f HOSTNAME 2000

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.

14. List and check coredump file.

esxcli system coredump file list

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15. Activate core dump file.

esxcli system coredump file set -e=TRUE

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16. List and check coredump file

esxcli system coredump file list

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17. Warning

The warning message should now have disappeared, that there is a coredump file configured.
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2 Comments

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by:RimFire007
Thanks for great video Andrew!

Need to ask obvious question.

1. Should I plug a (32GB?) USB3 Memory Stick to the server before performing these steps so that "dedicated" Memory Stick would be the target for the memory dumps?
2. Where the memory dumps will actually go after performing these steps?
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LVL 147
Thanks for your feedback.

In a production environment, you should not be using a USB or SD card anymore, hence why it is disabled.

but in answer to your question the USB/SD card in use, is the device already installed in the server, which ESXi is installed on and booted from!
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