vSphere 7 Partition Layout Changes

With the release of vSphere 7, VMware partitions are changed in the vSphere 7 layouts to make it more versatile and to allow additional VMware and third-party solutions to be installed on it. The VMware partition sizes in prior versions of vSphere 6.x were fixed and static which may prevent the installation of additional solutions such as vSAN, NSX-T, Tanzu as well as some third-party integrations. In response to these constraints, VMware modified the partition sizes in the vSphere 7 layout, increasing the size of boot banks and making them easier to extend.

In this article, we’ll learn about the vSphere 7 ESXi boot media partitions, important differences between ESXi 6 and ESXi 7, ESXi 7 supported boot media and upgrading to ESXi 7 with a new partition layout. Let’s get into it!

vSphere 7 – ESXi Boot Media Partition

With the new partition schema of the vSphere 7 layout, the system boot partition is the only one that is fixed at 100 MB. The rest of the VMware partitions are dynamic, which means the size of the partitions is decided by the boot media size. In the vSphere 7 layout, VMware consolidated the partitions which now consists of four VMware partitions.

• System Boot: The EFI components and boot loader are stored in a FAT16 partition called system boot. Like earlier vSphere versions, it’s a fixed-size partition of 100 MB.

• Boot-bank 0: A FAT16 partition that gives the system enough room to hold ESXi boot components. It’s a dynamic partition with a range of sizes ranging from 500 MB to 4 GB.

• Boot-bank 1: A FAT16 partition that gives the system enough room to hold ESXi boot components. It’s a dynamic partition with a range of sizes ranging from 500 MB to 4 GB.

• ESX-OSData: A VMFS-L partition that holds non-boot and additional modules like system states and configuration, as well as system VMs, and it’s only available on high-endurance systems. It’s also a dynamic partition with a storage capacity of up to 128 GB.

The ESX-OSData partition is separated into two high-level data types:

• ROM-data: Data produced rarely, such as VMtools ISOs, settings, and core dumps.

• RAM-data: Includes logs, VMFS global traces, vSAN EPD and traces as well as active databases, among other things.

Note that a VMFS datastore is automatically established for storing virtual machine data if the boot media is greater than 128GB.

Figure: vSphere 7 Layout

The ESX-OSData partition is built on a high-endurance storage device such as an HDD or SSD for storage media such as USB or SD cards. When a backup high-endurance storage device is unavailable, a VMFS-L Locker partition on USB or SD devices is created, although it is solely utilized to store ROM-data. A RAM disc is used to store RAM data.

Keep in mind that USB and SD devices are no longer supported starting vSphere 7 Update 3 following a large number of issues encountered by customers.

Key Changes Between the ESXi 6 And ESXi 7

The ESX-OSData partition change is an important one in the context of SD cards and USB devices since all non-boot partitions (such as the small and big core-dump, locker, and scratch disc ) have been consolidated into this new VMFS-L partition.

Figure: VMware Partitions in vShere 6.x and 7

High endurance persistent storage device required

Due to an increase in IO requests delivered to the ESX-OSData partition, it must be built on a high endurance persistent storage device. Multiple variables included with ESXi 7.x have resulted in higher IO requests, including:

• • A higher number of probe requests were issued to examine the device’s condition and ensure that it was still serving IO requests.

• • Scheduled routines to back up system state and timestamps contribute to the increased IO demands in a minor way.

• • Additionally, new features and solutions use ESX-OSData to store their configuration data, necessitating its installation on a high-endurance, locally connected persistent storage device.

Increased storage minimums

ESXi could previously be installed on 1 GB USB sticks. ESXi 7.0, on the other hand, increases these needs to 3.72GB of storage space to be precise.

However, the recommended storage capacity is 32 GB. What’s noteworthy is that, while the boot partition’s size (100MB) remains constant, the sizes of the other VMware partitions vary depending on the kind of installation media used.

• • <4GB minimum required to install ESXi 7.0.

• • 32 GB required to install ESXi 7.0.

• • 4GB required for upgrading to ESXi 7.0.

Dynamic partition sizes

The VMware examples demonstrate media sizes ranging from 4GB to 128GB and beyond, and as you can see, if you have an SSD drive with more than 128GB, the remaining space may be used to create a local datastore in ESXi partitions.

Figure: Changes in vSphere 7 Partitions

Supported Boot Media in vSphere 7 Layout

As you may be aware, starting with vSphere 7 Update 3, the use of standalone SD cards or USB devices is deprecated in the vSphere 7 layout. In which instance the system will display warnings when you use them. It is suggested (mandatory eventually) that you store the ESX-OSData partition on a locally attached persistent storage device.

A 32 GB disc is required when booting from a local drive, SAN or iSCSI LUN to create system storage volumes in ESXi partitions. A VMware Tools partition is created automatically on the RAM disc starting with ESXi 7 Update 3, and warnings appear to prevent you from establishing ESXi partitions on flash media devices other than the boot bank partitions. Other ways for improving the performance of an ESXi 7.0 installation include:

• • A 138 GB or bigger local drive for maximum ESX-OSData compatibility. The boot partition, ESX-OSData volume, and VMFS datastore are all located on the drive.

• • A device capable of storing a minimum of 128 terabytes of data (TBW).

• • A device with a sequential write speed of at least 100 MB/s.

• • A RAID 1 mirrored device is recommended for resiliency in the event of device failure.

Upgrading to ESXi 7 U3 with SD card

We’ve already discussed that starting with vSphere 7 Update 3, the use of standalone SD cards or USB devices is deprecated in the vSphere 7 layout. The system will continue to run with warnings if they are used but it is best that you store the ESX-OSData partition on a locally attached persistent storage device.

Upgrade procedure with SD card and additional disk

Please follow the procedures below to upgrade ESXi 6.7 with a standalone SD card or USB device to ESXi 7 with an extra disc. If the ESXi 6.7 host does not have persistent storage:

• • On an ESXi 6.x host, add a high-endurance, locally connected persistent storage device.

• • ESXi Host should be upgraded to ESXi 7 to meet ESXi requirements.

• • If autoPartition=True is set, the first unused boot device will be auto partitioned and utilized as the ESX-OSData partition.

• • This will guarantee that the System boot partition is stored on the SD card or USB device, and the ESX-OSData partition is stored on the newly inserted storage device with ESX partitioning.

If the ESXi host has previously been updated to ESXi 7.x and is operating from a USB or SD card.

• • Add a locally associated persistent storage device with good durability in ESXi partitions.

• • Set autoPartition = True on the ESXi host, and it will auto partition the first unused boot device to be used as the ESX-OSData partition.

• • This will guarantee that the System boot partition is stored on the SD card or USB device, and the ESX-OSData partition is stored on the newly inserted storage device with ESX partitioning.

ESXi 7.0 degraded mode

When a 4 GB boot device is used and no local disc is discovered, ESXi enters a state known as ‘degraded mode.’ In summary, the degraded mode is a condition in which logs and states may not be permanent, causing boot up to be delayed as a result.

Note that if the OSData partition is on an HDD or superior media, the system in the vSphere 7 layout will not enter in degraded mode.

Figure: The only vSphere 7 layout that will remain supported is the use of persistent storage devices only.

A sysalert appears in case you enter degraded mode:

ALERT: No persistent storage for system logs and data is available. Because ESX has a limited amount of system storage capacity, logs and system data will be lost in the vSphere 7 layout if the server is rebooted. To fix this, you’ll need to install a local disc or flash device and follow the steps in KB article 77009.

If you don’t want to use an SD card or USB device anymore in the vSphere 7 layout, you can:

• • Use a locally connected persistent storage device.

• • On a locally connected storage device, reinstall ESXi 7.x in the vSphere 7 layout.

• • Please refer to VMware KB Article 2042141 if you wish to backup and restore the configuration of ESXi.

• • This will ensure that all partitions are kept on a locally connected storage device with excellent durability in the vSphere 7 layout.

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Conclusion

While the new vSphere 7 layout will certainly bring hardship to customers with a large fleet of hypervisors installed on SD cards, it also introduces more flexibility to improve the integration of VMware and third-party solutions into the vSphere hypervisor.

With the new vSphere 7 layout, VMware is discontinuing support for Boot configuration with only an SD card, USB drive, and without a persistent device with the introduction of vSphere 7 Update 3.

Because these will not be supported in future vSphere versions, customers are encouraged to stop using SD cards and USB devices entirely due to the vSphere 7 layout. If that isn’t possible right now, make sure you have at least 8GB SD cards or USB drives on hand, as well as a minimum of 32 GB locally connected high endurance device for ESX-OSData Partition.