Just a quick overview about this new VMware update about vSphere 7 with USB/SD Cards and It will be discontinued in future vSphere versions. VMware launched a statement/information that customers should start planning to move away from USB/SD Cards for future releases KB85685.
VMware strongly advises that you move away completely from using SD card/USB as a boot device option on any future server hardware.
VMware strongly advises and highly recommends that our customers start to plan and transition to use a persistent device for boot and ensure that SD cards are not chosen as an option to use as a boot device while ordering new hardware for their environment. Most vendors provide alternate boot devices including M.2 options.Why can’t RAMDisk be used as a long-term option?
- RAMDisk (volatile memory as a disk) as storage for some areas was provided with 7.x as another option to mitigate some of the SD card reliability issues so that frequently accessed portions like scratch and VMTools could be stored. It will no longer be an option for the next major release of vSphere due to the following reasons:
- a. Use of RAMDIsk implies operation in degraded mode because RAMDisk is volatile, and as such a PSOD/power loss could result in loss of critical data and runtime state in the OSDATA partition.
- b. RAMDisk occupies additional space on memory that could expand when OSDATA expands. This space could have been used for VMs and applications.
- c. Memory is one of the most expensive components of server hardware
- d. Storing scratch etc. on RAMDisk could cause a supportability issue. Logs/Bundles etc. that depend on OSDATA partition cannot be reliably extracted anymoreWhat type of devices and interfaces is this KB referring to ?
- We are mainly referring to devices that are unreliable, such as SD cards with unpredictable and unreportable endurance.
- We are also referring to unreliable interfaces such as USB.
- Please note that when we refer to SAS, SATA, NVMe, etc., we imply that these devices have to be supported in their native formats and not through any conversions (such as NVMe or SAS to USB)
At the moment as long you apply the best practices to use SUB/SD Cards I don’t see any issues continuing to use this type of device to install vSphere, but you should start thinking to move that to an M.2 or another local persistent device as the standalone boot option.
Is this a good situation? No, but systems change from time to time. We have the same with some CPU versions that are supported in new versions and most of the time we cant install and need news servers. I have that problem with my homelab HP G7, so why using SD cards should be different or so scandalous?
ESXi 7 System Storage Contents
The sub-systems that require access to the ESXi partitions, access these partitions using the symbolic links. For example: /bootbank and /altbootbank symbolic links are used for accessing the active bootbank and alternative bootbank. The /var/core symbolic link is used to access the core-dumps.
ESXi 7 System Storage Sizes
Depending the boot media used and if its a fresh installation or upgrade, the capacity used for each partition varies. The only constant here is the system boot partition. If the boot media is larger than 128GB, a VMFS datastore is created automatically to use for storing virtual machine data.
As we can see in the above changes, Is still possible to install the vSphere 7 USB/SD Card(as long that we set the ESXi with the best practices while using this type of device), so we have some years until the next big vSphere version, and most of the companies will change their servers. We just need to adapt our vSphere configurations to the new partition changes and the impact that those have on USB/SD cards.
That been said, what is not admissible is that VMware tried(or had the idea after the U2a issue) to change this from today for the vSphere 7 and try to put the problem on vendors and customers. That is not admissible. But they have correct that and now is still supported(and in upgrades, they should improve the issue of the partition to work better with SD cards) but we need to start to think that we need to change our boot devices.
At the moment for new servers, I will always request servers with local disks (maybe I will start thinking to add M.2 devices) so while we are updating our servers (we always do around 2/3 or 4 years depending on the server and systems) so until vSphere 7 is EOL we have more than time to change all our servers. As long as we don’t have another issue similar to the U2a SD issue, I think we are ok.
In my opinion, VMware is forwarding to more Cloud and Kubernetes areas and in the future, there will not be a VMware Hypervisor, only used as an Infrastructure Layer to support Kubernetes/Cloud infrastructures.
VMware has also another “problem” that is their license price. It has a huge impact on big customers(particularly the hosting and cloud customers) budged and some are already checking alternatives for their Hypervisor servers.
More information about vSphere 7 partitions layout and changes.:
New update from VMware about this subject: https://blogs.vmware.com/vsphere/2021/09/esxi-7-boot-media-consideration-vmware-technical-guidance.html
Previous blog posts about this vSphere 7 and USB/SD Cards:
Hope this blog post new VMware update about vSphere 7 with USB/SD Cards will help you clarify what is the future of USB/SD Cards in the vSphere environment.
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