An NFS appliance can be deployed as a forward-proxy data cache or as a reverse-proxy accelerator.
In a forward-proxy deployment, the appliance is remote from the data center where it caches popular data giving the end-user faster access to information.
In a reverse-proxy deployment or accelerator mode, the appliance is local to the administrative data center where it is used to offload work from busy file servers and free system resources.
In a forward-proxy deployment, the appliance is placed as close as possible to the remote office. Client requests are then explicitly directed to the appliance. This means that a client request for NFS is directed to the cache as opposed to the source file server. If valid data exists in the cache, that data or file is served directly to the client. If the data does not exist on the cache, it is retrieved from the source file server, written to disk on the appliance, and subsequently served to the client.
A forward-proxy deployment consolidates data at remote locations to free bandwidth and provide fast access to information. The following example illustrates such a forward-proxy deployment.
In a reverse-proxy deployment, an appliance is used to offload busy data servers. Frequently accessed data, or "hot objects" are replicated and cached by the appliance. This supersedes full dataset replication by eliminating the requirement to push a full set of data to a remote location. Along with saving bandwidth, the appliance puts only the data that you need where you need it. The following example illustrates a reverse-proxy deployment.
A proxy configuration requires the administrator to explicitly provide the proxy IP address for NFS client, to direct requests to the proxy device. In this type of deployment, authenticated users know that the proxy exists and can simply remove the proxy information in order to bypass the cache.
Copyright © 1994-2002, Network Appliance, Inc. All rights
reserved.
Part No. 210-00319
File: pfs5.htm
Last updated: 11/12/02 13:06:05