6.0.1

Table Of Contents
Cause
ESXi does not recognize certain devices as flash disks when their vendors do not support automatic flash
disk detection. In other cases, some non-SATA SAS flash disks might not be detected as local. When disks
are not recognized as local flash disks, they are excluded from the list of flash disks available for such
features that require only local flash disks.
Solution
You might need to manually tag disks as flash disks 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.
Mark Storage Devices as Flash
If ESXi does not automatically recognize its devices as flash, mark them as flash devices.
ESXi does not recognize certain devices as flash when their vendors do not support automatic flash disk
detection. The Drive Type column for the devices shows HDD as their type.
CAUTION Marking HDD disks as flash disks could deteriorate the performance of datastores and services
that use them. Mark disks as flash disks only if you are certain that those disks are flash disks.
Prerequisites
Verify that the device is not in use.
Procedure
1 Browse to the host in the vSphere Web Client object navigator.
2 Click the Manage tab, and click Storage.
3 Click Storage Devices.
4 From the list of storage devices, select one or several HDD devices that need to be recognized as flash
devices and click the Mark as Flash Disks icon.
5 Click Yes to save your changes.
The type of the devices changes to flash.
What to do next
If the flash device that you mark is shared among multiple hosts, make sure that you mark the device from
all hosts that share the device.
Mark Storage Devices as Local
ESXi enables you to mark devices as local. This is useful in cases when ESXi is unable to determine whether
certain devices are local.
Prerequisites
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Make sure that the device is not shared.
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Power off virtual machines that reside on the device and unmount an associated datastore.
Procedure
1 Browse to the host in the vSphere Web Client object navigator.
2 Click the Manage tab, and click Storage.
vSphere Troubleshooting
72 VMware, Inc.