New Kernel options available on ESXi 7.0
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New Kernel options available on ESXi 7.0


Article ID: 313264


Updated On:


VMware vSphere ESXi


ESXi 7.0 introduces significant changes to the disk partition layout on boot devices, which includes:
  • larger system boot partition
  • larger boot banks
  • consolidation of coredump, tools and scratch into a single VMFS-L based ESX-OSData volume
  • coredumps default to a file in ESX-OSData

This article provides information about new and updated boot options in ESXi 7.0 to facilitate the changes mentioned.


VMware vSphere ESXi 7.0.0


The following boot options can be passed in at boot time either by adding them to the end of the kernelopt line in the ESXi boot.cfg file or entering them manually by pressing Shift-O in the boot loader. For more information, see the About the boot.cfg File  section of the Install Guide and Enter Boot Options to Start an Installation or Upgrade Script section of the Upgrade Guide.

autoPartition=TRUE/FALSE (default FALSE)

This option toggles automatic partitioning of unused local storage devices upon boot. The boot disk will be partitioned with system-storage volumes, i.e. boot banks, ESX-OSData and VMFS datastore (if the disk is larger than 128GB). The other disks are partitioned with VMFS. If the option is stored in boot.cfg, then any new empty device discovered will also be autoPartitioned. In addition to this option, auto-partitioning can be limited to only the first unused device by setting autoPartitionOnlyOnceAndSkipSsd=TRUE.
For systems that have USB boot devices and a VMFS-L ESX-OSData volume does not exist on other local disks:
  • If a scratch partition (along with any immediate coredump partition on the same storage device) has been configured on the system, then the partition gets converted to ESX-OSData.
  • Else, the first identified unused device will also be partitioned with ESX-OSData

skipPartitioningSsds=TRUE/FALSE (default FALSE)

If this option is TRUE, then local SSDs are skipped from auto-partitioning.

autoPartitionOnlyOnceAndSkipSsd=TRUE/FALSE (default FALSE)

When TRUE, SSD/NVMe devices are skipped and ESXi will only auto-partition the first unused local disk if the system does not have a VMFS-L ESX-OSData volume.

allowCoreDumpOnUsb=TRUE/FALSE (default FALSE)

This option enables permission for ESXi to write kernel crash coredumps to the VMFS-L Locker volume on the USB boot device.

dumpSize (default: 0 (automatically sized))

The dumpSize option customizes the size of the core dump file to be created on the system VMFS-L volume. For example, dumpSize=5120 creates a core dump file of 5120 MB. Note that the file's size is limited to half of the available space on the VMFS-L volume.

autoCreateDumpFile=TRUE/FALSE (default TRUE)

Toggles whether a coredump file is automatically created on the system. The attempted order of creating the coredump file is first to the VMFS-L ESX-OSData, then to USB VMFS-L, and finally a local VMFS datastore.

Deprecated kernel boot options

These options are no longer supported in ESXi 7.0:
  • –no-auto-partition
  • autoPartitionCreateUSBCoreDumpPartition
  • autoPartitionDiskDumpPartitionSize