6.7

Table Of Contents
NFS 4.1 provides multipathing for servers that support the session trunking. When the trunking is
available, you can use multiple IP addresses to access a single NFS volume. Client ID trunking is not
supported.
NFS and Hardware Acceleration
Virtual disks created on NFS datastores are thin-provisioned by default. To be able to create thick-
provisioned virtual disks, you must use hardware acceleration that supports the Reserve Space
operation.
NFS 3 and NFS 4.1 support hardware acceleration that allows your host to integrate with NAS devices
and use several hardware operations that NAS storage provides. For more information, see Hardware
Acceleration on NAS Devices.
NFS Datastores
When you create an NFS datastore, make sure to follow specific guidelines.
The NFS datastore guidelines and best practices include the following items:
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You cannot use different NFS versions to mount the same datastore on different hosts. NFS 3 and
NFS 4.1 clients are not compatible and do not use the same locking protocol. As a result, accessing
the same virtual disks from two incompatible clients might result in incorrect behavior and cause data
corruption.
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NFS 3 and NFS 4.1 datastores can coexist on the same host.
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ESXi cannot automatically upgrade NFS version 3 to version 4.1, but you can use other conversion
methods. For information, see NFS Protocols and ESXi.
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When you mount the same NFS 3 volume on different hosts, make sure that the server and folder
names are identical across the hosts. If the names do not match, the hosts see the same NFS
version 3 volume as two different datastores. This error might result in a failure of such features as
vMotion. An example of such discrepancy is entering filer as the server name on one host and
filer.domain.com on the other. This guideline does not apply to NFS version 4.1.
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If you use non-ASCII characters to name datastores and virtual machines, make sure that the
underlying NFS server offers internationalization support. If the server does not support international
characters, use only ASCII characters, or unpredictable failures might occur.
Firewall Configurations for NFS Storage
ESXi includes a firewall between the management interface and the network. The firewall is enabled by
default. At installation time, the ESXi firewall is configured to block incoming and outgoing traffic, except
traffic for the default services, such as NFS.
Supported services, including NFS, are described in a rule set configuration file in the ESXi firewall
directory /etc/vmware/firewall/. The file contains firewall rules and their relationships with ports and
protocols.
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