What’s New in vSphere 7.0 – Change in Storage Layout

Change in Storage Layout

With the introduction of vSphere 7.0. Vmware has made some big change in Storage Layout and also with the way their products used to work. One of their major changes in the Storage Layout, which was pretty much standard earlier.

Pre ESXi 7.0 Layout:


The Existing Pre ESXi 7.0 Layout has 7 Partitions, which used to indicate change. For example, it was very difficult to load Large modules and adding Third Party Components. 

There was a big Limitation of the Partition Sizes as they were fixed as well as the Number of Partitions was Hard-coded.

Due to these reason the current partition layout was not flexible.


New and Improved Storage Layout:


ESXi 7.0  has only four partitions.

  • System boot

Stores boot loader and EFI modules.

Type: FAT16

  • Boot-banks (x2)

System space to store ESXi boot modules

Type: FAT16

  • ESX-OSData

Acts as the unified location to store extra (nonboot) modules, system configuration and state, and system VMs

Type: VMFS-L

Should be created on high-endurance storage devices

Divided into two high-level categories of data called ROM data and RAM data:

    • RAM data: Frequently written data, for example, logs, vmfs global traces, vSAN EPD and traces, and live databases.
    • ROM data: Infrequently written data, for example, vmtools isos, configurations, and core dumps.
      /productLocker, /locker, /var/core, /usr/bin/vmware/isoimages, /usr/bin/vmware/floppies
  • VMFS Datastore

Customer space to store VMs

Type: VMFS

ESXi 7.0 partition sizes are based on the target storage size.

For storage media such as USB or SD devices, the ESX-OSData partition is created on a high-endurance storage device such as an HDD.

Where a secondary high-endurance storage device is not available, ESX-OSData is created on USB or SD devices, but this partition is used only to store ROM data. RAM data is stored on the RAM disk.

Upgrade Scenario:

For storage endurance requirements, see VMware knowledge base article 2145210 at https://kb.vmware.com/s/article/2145210.


Media Type



Local disk


Upgrade and install

Networked LUN


Upgrade and install

PXE boot (diskless systems)

Network booted

Not supported

USB-only media

USB or SD storage used for ESXi.

USB or SD has boot banks, locker, and core.

Upgrade (degraded operating mode)

USB with HDD for extra partitions

USB contains boot banks, locker, and core partitions.

Scratch partition is on the HDD.


Note: On the power cycle, degraded mode loses state, such as the configuration state (state.tgz).


Upgrade Requirements:

  • ESXi version 6.5 or later
  • Boot media size of 4 GB
The upgrade process performs a backup of critical and persistent data before destroying existing partitions. Because available storage space for the backup cannot be guaranteed, the installer backups the contents in RAM and restores them when the new partition layout is created.

Backup includes the following components:

  • ESXi host configuration files
  • VMware Tools ISOs in the locker partition
  • vSAN data in locker

The new install requirements for ESXi 7.0 are:

  • Recommended: 32 GB boot media
    • Supported: 4 GB
  • boot media GUID partition table (GPT) is  used for boot media partitioning
  • Datastore volume is not created on USB/SD media
  • Some media devices have vendor partitions. Installer creates ESXi system partitions to offset these existing partitions.


In case if you come across any issues while doing the upgrade or installation you can review the below log locations for the reason for failure:

Log File 



Installer Logs


Upgrade Logs


Kernel Boot Logs

Ashutosh Dixit

I am currently working as a Senior Technical Support Engineer with VMware Premier Services for Telco. Before this, I worked as a Technical Lead with Microsoft Enterprise Platform Support for Production and Premier Support. I am an expert in High-Availability, Deployments, and VMware Core technology along with Tanzu and Horizon.

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