Prepare for VMware vSphere 8.0 / vSphere.Next by reading updated KB 85685 "SD card/USB boot device revised guidance"


If you are a VMware vSphere administrator preparing for the upcoming vSphere 8.0 / vSphere.Next, then this article is for you! Yes, the information here is critical to ANY virtualization home lab enthusiast, and/or any VMware administrator who is planning out how and where they'll be installing or upgrading to VMware ESXi 8.0 hypervisor. This popular KB has 82,545 views already, and I was automatically alerted to this significant KB update via email yesterday because I had used the handy "Subscribe" button months ago.

I encourage you to read VMware KB 85685 in its entirety, with some crucial excerpts quoted below to hopefully get your attention:

  • VMware KB 85685
    SD card/USB boot device revised guidance (85685)

    VMware will continue supporting USB/SD card as a boot device through the vSphere.Next product release, including the update releases. Both installs and upgrades will be supported on USB/SD cards. The change from the previous guidance is that SD/USB as a standalone device will now be supported on previously certified server platforms. Customers can still however provision an additional persistent device to store the OSData partition, which VMware recommends. ESX will attempt to relocate the critical regions to such a persistent device. Starting from 7.0U3c, if an USB SD card boot device is detected during installs and upgrades, critical regions of the OSData partition such as VMTools and scratch will automatically be moved out. Moreover with vSphere.Next, the entire OSData partition can be moved out.

I found it a little surprising that VMware already called out 8.0 on the April 27 2022 update to this KB, then on April 28 2022 they apparently changed every 8.0 reference to vSphere.Next instead. Hmm, I can guess that somebody at VMware MarCom (Marketing Communications) had a fit about this. If VMware does wind up calling it vSphere.Next when whenever it gets officially announced, hopefully itโ€™s better received than the renaming of VMworld to VMware Explore was.

You can have a look for yourself by traveling back in time to the last time Web Archive grabbed this KB 85685 on March 17 2022 here, but for some reason, it doesn't pull up right now.

Check out this KB 85685 excerpt:

Guidelines for vSphere Boot Devices

A SATA/SAS/NVMe SSD that meets VMware specified endurance requirements, or HDD is strongly recommended.

Boot Device:
High-Quality Media: PCIe NVMe, SAS, SATA/SATADOM SSD
Industrial grade flash/SSDs, SLC or pSLC

Boot Device Size:
32GB** minimum (must), 128GB** recommended

Endurance requirements:
128 TBW (over 5 years)

IO Performance
At least 100MB/s
Please refer to the ESXi hardware requirements here:
** GB here equals 1024x1024x1024 (2^30=1,073,741,824) bytes as opposed to 10^9 bytes (1,000,000,000)



We now have some very specific hardware guidance. For example, an older consumer SSD like the modest, smallest, and slowest variant of Samsung 960 EVO M.2 NVMe SSD is rated at:

  • 100 TBW (TeraBytes Written)
  • 3,200MB/s reads
  • 1,500MB/s to 1,900MB/s writes, depending upon size

In other words, it's more than good enough to run your ESXi 8.0 on for years to come, even if you pound on it with vSAN. It has no warranty for such use, and you'll be unlikely to ever find such non-PLP protected consumer SSDs on a VMware Compatibility Guide, but it should be just fine, as long as you're not using it for vSAN itself.


Transcend 256GB SATA III 6Gb/s MTS430S 42 mm M.2 SSD Solid State Drive [TS256GMTS430S]

If you have a M.2 form factor slot that supports AHCI/SATA (B+M Key) instead of NVMe, that slot would be the best choice to use your ESXi 8.0 going forward. Now you just need to see if you can find one that meets the specs above.

For example, Transcend M.2 SSD 430S in the 256GB size is rated at 140 TBW and 530 MB/s reads and 400 MB/s writes, so it exceeds the requirements, but the 128GB version does not.



Even the 2015's original consumer (M Key) Samsung 950 Pro NVMe M.2 256GB specifications indicate 200 TBW, and 2,200 MB/s read and 900 MB/s writes, exceeding the minimum specs. Gladly, I have some around that I wrote about back in 2015.


I might be going with SATADOM instead, to keep my M.2 slots for my super speedy VMFS datastores, where speed really matters. We'll see. That is, if I can find a device that exceeds those specs. It's sure seeming that the choice of boot device for home labs might be a worthwhile topic for a future article...

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See also

  • Moving off of SD Boot Media
    Mar 15 2022 by Mike Foley at


    Recent changes in ESXi 7 have prompted many customers to consider moving from SD Cards and USB sticks as their ESXi boot media and back to SSDโ€™s or NVME drives. We here within VMware with lab systems are not immune to this challenge! I recently had some SSDs installed in my vSAN cluster so I could move from the SD card to using SSD drives as the boot device for my hosts. This blog post will go over the steps I took to accomplish this.