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Known limitations of the Intel® Xeon® processor E5 v3 series with ESXi 5.1.x, ESXi 5.5, and 6.0 (2087032)

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Details

This article provides the information on the following known limitations of the Intel® Xeon® processor E5 v3 series with ESXi 5.1.x, ESXi 5.5.x, and ESXi 6.0.x:
  • ESXi 5.1 and ESXi 5.5 earlier than 5.5 U3b do not support the Cluster-On-Die feature on Intel Xeon processor E5 v3 series.
  • Time Stamp Counters (TSCs) might not be in sync at boot on Intel Xeon processor E5 v3 series.
  • ESXi 5.1, ESXi 5.5, and ESXi 6.0 might fail to boot if TXT is disabled but TPM is enabled in the system BIOS of the host with Intel Xeon processor E5 v3 series.
  • ESXi shows 4 pCPU instead of actual 2 pCPU

Solution

These sections give the details about the limitations of the Intel Xeon processor E5 v3 series on VMware ESXi releases.

ESXi 5.1 and  ESXi 5.5 do not support the Cluster-On-Die feature on Intel Xeon processor E5 v3 series

vSphere ESXi 5.5 earlier than 5.5U3b does not support the Cluster-On-Die feature on Intel Xeon processor E5 v3 series. However, ESXi 5.5U3b does provide support for the Xeon E5 v3 processor:
Note: For additional information about current ESXi support for the Cluster-on-Die feature, see Intel Cluster-on-Die (COD) Technology, and VMware vSphere 5.5 U3b and 6.x (2142499).
 
To work around the issue that the ESXi 5.x kernel earlier than 5.5U3b does not show the correct number of processors, disable the Cluster-on-Die feature of the Intel Xeon processor E5 v3 series processor in the system BIOS.

TSCs on all the CPUs might not be in sync on certain systems with Intel Xeon processor E5 v3 series

vSphere expects processor TSCs to be in sync at boot for correct and efficient virtual machine operation. However, on certain systems with Intel Xeon processor E5 v3 series, the TSCs might not be in sync at boot.
 
In the vmkernel.log file, you see entries similar to:

0:00:00:19.140 cpu0:32768)Timer: 928: TSC disabled as reference timer: not in sync at boot time
0:00:00:19.150 cpu0:32768)Timer: 4139: reference timer is 24-bit ACPI PM at 3579545 Hz

Note: The preceding log excerpts are only examples. Date, time, and environmental variables may vary depending on your environment.

In ESXi 5.5 Update 2, this issue is resolved by forcing all the processors into the same P-state at boot before the software attempts to synchronize the TSCs.

ESXi 5.1 with patch ESXi510-201407001 has no workaround for this limitation. A microcode update from Intel is required to resolve this issue.

ESXi 5.1, ESXi 5.5, and ESXi 6.0 might fail to boot if TXT is disabled but TPM is enabled in the system BIOS of a host with Intel Xeon processor E5 v3 series

Some systems with Intel Xeon processor E5 v3 series might expose BIOS options for both Trusted Platform Module (TPM) and the Trusted Execution Technology (TXT) features. On such systems, the ESXi host might fail to boot if TXT is disabled but TPM is enabled in the BIOS. This issue occurs as the ESXi host needs both the features to be disabled in the BIOS for a successful boot.

To work around this issue, ensure that TPM is disabled along with TXT in the BIOS during the configuration of the system BIOS.

Additional Information

For translated versions of this article, see:

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