Snapshot fails for VM with running Docker container

Recently I noticed some Linux VM backups were failing and sometimes even crashing with following errors:
An error occurred while taking a snapshot: msg.snapshot.error-QUIESCINGERROR.
An error occurred while saving the snapshot: msg.snapshot.error-QUIESCINGERROR.

On closer look another error was visible in hostd.log file – Error when enabling the sync provider.

All of these VMs had one thing in common – they were running Docker containers.
I was not able to figure out why it happened but I was able to find a workaround – disable the VMWare Sync driver.

Copy-paste from Veritas KB article –

Steps to Disable VMware vmsync driver
To prevent the vmsync driver from being called during the quiesce phase of a VMware snapshot, edit the VMware Tools configuration file as follows:

1) Open a console session to the Redhat Linux virtual machine.
2) Navigate to the /etc/vmware-tools directory
3) Using a text editor, modify the tools.conf file with the following entry

enableSyncDriver = false

Note: If the tools.conf file does not exist, create a new empty file and add the above parameters.



ESXi will not resume syslog log sending when destination has been down for some time

Recently I was playing with ESXi syslog and Logstash + Graylog. For some reason Logstash instance died. After restarting the Logstash only some ESXi hosts resumed log sending. Quick google search revealed that it is a know issue and solution is to reload syslog on the host. After running following script in PowerCLI against my vCenter the log sending resumed.

$hosts = Get-VMHost
foreach($vihost in $hosts){
$esxcli = get-vmhost $vihost | Get-EsxCli

Good information about PowerCLI and ESXCLI:


Firmware update fails on HPE server when Serial Number and Product ID is missing

Recently I was having issues updating HPE ProLiant BL460c G7 with latest SPP (2016.10). Firmware update just stopped on Step 1. Also HPE custom ESXi ISO failed to work.

After some digging around I discovered that server Serial Number and Product ID were missing. I went to BIOS and filled in the correct Serial Number and Product ID and after that the firmware update worked and I was also able to install HPE custom ESXi.

I suspect that the Serial Number and Product ID were lost when this blade server was removed from one Virtual Connect infrastructure and placed to another.

Error joining ESXi host to Active Directory

I was trying to join ESXi host to Active Directory using PowerCli ( Get-vmhost <vmhost> | Get-VMHostAuthentication | Set-VMHostAuthentication -JoinDomain -Domain “” -User “<username>” -Password “<password>” ) and I was getting an error:

Active directory authentication store is not supported for VMHost <hostname>

Tried to join it via old C client – that failed also.

AD join finally worked via VMware Host Client running on the host. VMWare Host Client can be accessed via web browser – https://<hostname>/ui/#/login.

Error during vMotion: The source detected that the destination failed to resume.

During a vMotion one of my VMs refused to move and vCenter was giving a following error:

The VM failed to resume on the destination during early power on.
Module DiskEarly power on failed.
Cannot open the disk ‘/vmfs/volumes/…./…./???????.vmdk’ or one of the snapshot disks it depends on.
Could not open/create change tracking file

I turned the server off and tried to delete the change tracking file. Got an error:

Cannot delete file [<Datastore>] VMFolder/VM-ctk.-vmdk

Migrated the VM to another host and tried power it on. Got an error:

An error was received from the ESXi host while powering on VM VMName.
Failed to start the virtual machine.
Cannot open the disk ‘/vmfs/volumes/5783364b-08fc763e-1389-00215a9b0098/’ or one of the snapshot disks it depends on.
Could not open/create change tracking file

Next I rebooted the ESXi host on which the problematic VM was initially and after that I was able to delete the *-ctk.vmdk file and power on the VM. It seems that for some reason there was a file locks on the change tracking files and it prevented operations on the VM.

No coredump target has been configured

I was doing a hardware upgrade for some of the VMWare hosts in lazy fashion. I pulled the disk (small SATA SSD) from old host (HP BL460c Gen8) and inserted it into new host (HP BL460c Gen9). The old hosts used SAS HBA and the new hosts are using integrated SATA controller.

Using this method I avoided the unnecessary re-installation of the hosts. But when they booted I got warning message – “No coredump target has been configured. Host core dumps cannot be saved.”

Update 12.08.2016 – Starting from ESXi 5.5 U3 build 4179633 this issue will fix it self automatically. You can read more from here.

I turned to KB article 2004299 to fix it but I had to do a little more than described there.

My fix process was following:

  • Logged in to ESxi via SSH
  • esxcli system coredump partition get returned – “Not a known device: naa.xxxxxxxxxxxxxxxxxxxxxxxxxxx”
  • Executed following command to list all the disks and find the SSD disk I was booting from: esxcli storage core path list | more
  • My SSD disk was “Runtime Name: vmhba0:C0:T0:L0”, “Device: t10.ATA_____MO0100EBTJT_____________________________S0RFNEAC603385______”
  • Executed following command to list partitions on my disk –  “esxcli storage core device partition list -d t10.ATA_____MO0100EBTJT_____________________________S0RFNEAC603385______”
  • Identified that my coredump partition is number 7 (type fc)
  • Executed following command to set the partition: esxcli system coredump partition set –partition=”t10.ATA_____MO0100EBTJT_____________________________S0RFNEAC603385______:7″
  • Executed the following command to activate the partition: esxcli system coredump partition set –enable true
  • esxcli system coredump partition get now returns and the warning message dissipated:
    Active: t10.ATA_____MO0100EBTJT_____________________________S0RFNEAC603385______:7
    Configured: t10.ATA_____MO0100EBTJT_____________________________S0RFNEAC603385______:7


128GB DDR4-2400 Memory Kit available for HPE servers

HPE has made available 128GB (1x128GB) Octal Rank x4 DDR4-2400 CAS-20-18-18 Load Reduced Memory Kit (HPE info page). The price as of writing this (13.07.2016) is quite high – 9499 USD.

The 128GB RAM module open up possibilities to build single socket systems with up to 1,5TB of RAM.

Example HP ProLiant DL380 Gen9 config:

  • 1 x Intel Xeon E5-2699v4 (2.2GHz/22-core/55MB/145W)
  • 12 x HPE 128GB (1x128GB) Octal Rank x4 DDR4-2400 CAS-20-18-18 Load Reduced Memory Kit

Reducing the number of sockets could lower the amount of software licenses needed – eg VMWare.