NAS Transport for VMware
The NAS (network attached storage) transport mode enables the virtual server agent (VSA) proxy computer to read data directly from the network file server (NFS), without going through an ESX host or transferring data over the local area network (LAN).
When the automatic transport mode selection feature is enabled, and the NAS storage is connected to the ESX host, the NAS transport mode is automatically selected for the supported backup and restore operations. With this, the VSA must have access to the datastore NFS volume exports that provide storage for the virtual machine disks. Data is read directly from the storage where the virtual machines reside, without going through the ESX host or transferring data over the LAN between the ESX host and the VSA proxy. The ESX host is contacted only to coordinate access to the NFS datastore.
You can use the NAS transport mode for the following operations:
- Streaming backup operations
- Backup copy operations
- Restoring full VM operations.
The benefits of using the NAS transport mode for backup and restore operations are as follows:
- The NAS transport mode does not require an ESX proxy host computer.
- The NAS transport mode can reduce the need for mount operations.
- The NAS transport mode increases the performance of streaming backup operations and backup copy operations because the data is directly transferred from the NFS to the proxy computer (which is the MediaAgent).
When to Use the NAS Transport Mode
Use the NAS transport mode in the following scenarios:
- The Virtual machines that are backed up are on NFS datastores.
- Each proxy that performs backup operations is a Windows physical server, a Linux physical server, or a Linux virtual machine proxy with access to datastore LUNs.
- Each MediaAgent has local access to directly connected storage using a shared mount path.
Do not use the NAS transport mode in the following scenarios:
- Local datastores are available only within the ESX server environment.
- The storage where the virtual machines reside is accessed using the Fibre Channel Protocol (FCP) or the iSCSI SAN protocol.
Consider the following when using the NAS transport mode:
- For streaming operations, Windows VSA VM proxies use the HotAdd mode instead of the NAS transport mode because HotAdd performs better.
- For other NFS storage vendors, the hardware snapshot datastore is mounted to a proxy ESX server, and therefore, uses the NAS transport mode during backup operations.
- In a physical proxy configuration, the VSA and the MediaAgent are installed on a physical server that can connect to the NAS network. Backups in a purely physical implementation include only NAS devices.
- For backup copy operations and restore from IntelliSnap operations, the following are true:
- You can perform ESX proxyless backup copy operations (that is, backups that do not have a proxy ESXi host) with an explicit selection of the NAS transport mode only for NetApp.
- For NetApp NFSv4 and other NFS storage vendors, the hardware snapshot datastore is mounted to a proxy ESX server. Therefore, the datastore uses the NAS transport mode for backup operations.
- Live Browse for IntelliSnap uses the NBD (network block device) transport mode.
- You can use the NAS transport mode only with proxy computers that are hosted on Windows physical computers, Linux physical computers, and Linux virtual machines. If the proxy is hosted on a Windows virtual machine, then use a HotAdd configuration to deploy a proxy.
- VSA proxies must have access to NFS exports from the NFS server.
- The proxy machine must have access to the NFS ports for the destination NFS server behind any firewall configuration.
- When running as root, libnfs tries to allocate a system port for its connection to the NFS server. When running as non-root, libnfs uses a normal ephemeral port. By default, many NFS servers do not allow non-system ports to connect. For these NFS servers, you must use the "insecure" export option in /etc/exports to allow libnfs clients to connect.
Last modified: 7/23/2019 5:28:06 PM