6.5.1

Table Of Contents
Problem
By default, auto-partitioning deploys VMFS file systems on any unused local storage disks on your host,
including flash disks.
However, a flash disk formatted with VMFS becomes unavailable for such features as virtual flash and
vSAN. Both features require an unformatted flash disk and neither can share the disk with any other file
system.
Solution
To ensure that auto-partitioning does not format the flash disk with VMFS, use the following boot options
when you install ESXi or boot the ESXi host for the first time:
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autoPartition=TRUE
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skipPartitioningSsds=TRUE
If you use Auto Deploy, set these parameters on a reference host.
1 In the vSphere Web Client, select the host to use as a reference host and click the Configure tab.
2 Click System to open the system options, and click Advanced System Settings.
3 Scroll to VMkernel.Boot.autoPartition and set the value to true.
4 Scroll to VMkernel.Boot.skipPartitioningSsds and set the value to true.
5 Reboot the host.
If flash disks that you plan to use with Flash Read Cache and vSAN already have VMFS datastores,
remove the datastores.
Local Flash Disks Are Undetectable
If you query for local flash disks, the ESXi host might not return a complete list of the local flash disks.
Problem
ESXi might not be able to detect flash disks, or recognize them as local. This problem can occur when
you configure entities that require only local flash disks, for example, virtual flash resource or vSAN.
Cause
ESXi does not recognize certain devices as flash disks when their vendors do not support automatic flash
disk detection. In other cases, some flash disks might not be detected as local, and ESXi marks them as
remote. When the host does not recognize the disks as the local flash disks, it excludes them from the list
of disks available for configuration.
Solution
You might need to tag the disks as flash or as local.
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If ESXi does not automatically recognize its disks as flash disks, tag them as flash disk disks.
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If ESXi does not detect flash disks as local, manually set them as local.
vSphere Troubleshooting
VMware, Inc. 75