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Table Of Contents
Non-VVols virtual machines of hardware version 11 or later use separate files to store their memory
snapshots. This usage is consistent with VMs on vSphere Virtual Volumes storage, where memory
snapshots are created as separate VVols instead of being stored as part of a .vmsn file in the VM home
directory. In contrast, non-VVols VMs with hardware version 10 continue to store their memory snapshots
as part of the .vmsn file in the VM home directory. As a result, you might experience problems or failures
when attempting to migrate these VMs between virtual and nonvirtual datastores.
Solution
To avoid problems when migrating VMs with memory snapshots across virtual and nonvirtual datastores,
use hardware version 11. Follow these guidelines when migrating version 10 or earlier VMs with memory
snapshots:
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Migrating a version 10 or earlier VM with memory snapshots to a virtual datastore is not supported.
The only workaround is to remove all snapshots. Upgrading the hardware version does not solve this
problem.
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Migrating a version 10 or earlier VM with memory snapshots from a virtual datastore to a nonvirtual
datastore, such as VMFS, can succeed. However, the migration might put the VM in an inconsistent
state. The snapshots that were taken on the virtual datastore use the vmem object. Any memory
snapshots taken after migrating to VMFS are stored in the .vmsn file. If you later attempt to migrate this
VM back to vSphere Virtual Volumes storage, your attempt fails. As with the previous case, remove all
snapshots to work around this problem.
Troubleshooting VAIO Filters
vSphere APIs for I/O Filtering (VAIO) provide a framework that allows third parties to create software
components called I/O filters. The filters can be installed on ESXi hosts and can offer additional data services
to virtual machines by processing I/O requests that move between the guest operating system of a virtual
machine and virtual disks.
For information about I/O filters, see the see the vSphere Storagepublication.
Handling I/O Filter Installation Failures
Typically, all ESXi hosts in a cluster have the same set of I/O filters installed. Occasionally, failures might
happen during installation.
If an I/O filter installation fails on a host, the system generates events that report the failure. In addition, an
alarm on the host shows the reason for the failure. Examples of failures include the following:
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The VIB URL is not accessible from the host.
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The VIB has an invalid format.
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The VIB requires the host to be in maintenance mode for an upgrade or uninstallation.
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The VIB requires the host to reboot after the installation or uninstallation.
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Attempts to put the host in maintenance mode fail because the virtual machine cannot be evacuated
from the host.
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The VIB requires manual installation or uninstallation.
vCenter Server can resolve some failures. You might have to intervene for other failures. For example, you
might need to edit the VIB URL, manually evacuate or power off virtual machines, or manually install or
uninstall VIBs.
Chapter 7 Troubleshooting Storage
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