Recursive ascent network link failure notifications

Abstract

A method for transparently recovering from a network link failure within the context of a single network request/response operation between a client and a server is disclosed. The method requires a robust network infrastructure that provides multiple paths from the client to the server. When a network link fails, network traffic is re-routed around the failure and the request is successfully processed without the client or the server even being made aware of the failure. An error indication is returned to the client system only when the network infrastructure does not provide an alternate path that allows the request to be successfully processed.

What is claimed is: 
     
         1 . In a computing system where a data request has been passed between an upstream site and a file service proxy cache node, the file service proxy cache node being a network node located between the upstream site and the origin file system node, a non-transitory computer-readable storage medium including instructions that, when executed by the file service proxy cache node, performs the steps:
 the file service proxy cache node determining that communication between the file service proxy cache node and the origin file system node has been interrupted;   determining whether an alternate route for communication between the file service proxy cache node and the origin file system node is available;   if the alternate route for communication between the file service proxy cache node and the origin file system node is available:
 obtaining the data to fulfill the data request from the origin file system node over the alternate route for communication between the file service proxy cache node and the origin file system node; and 
 transferring the data to the upstream site with an error code indicating success; and 
   if the alternate route for communication between the file service proxy cache node and the origin file system node is unavailable:
 reporting an error code to the upstream site. 
   
     
     
         2 . The system of  claim 1 , wherein determining if an alternate route is available includes searching a directory tree for an alternate route. 
     
     
         3 . The system of  claim 2 , wherein searching the directory tree includes searching for connections by a second file service proxy cache node to the origin file system node. 
     
     
         4 . The system of  claim 1 , wherein determining if an alternate route is available includes communicating with a second file service proxy cache node to determine if the second file service proxy cache node has a connection to the origin file system node. 
     
     
         5 . The system of  claim 1 , wherein the upstream site includes a client system. 
     
     
         6 . The system of  claim 1 , wherein the upstream site includes a client terminator. 
     
     
         7 . The system of  claim 1 , wherein the upstream site includes a second file service proxy cache node. 
     
     
         8 . The system of  claim 1 , wherein the file service proxy cache node is connected to the origin file system node through a second file service proxy cache node. 
     
     
         9 . The system of  claim 1 , wherein the data request includes a flush request, wherein the flush request includes data to save in a stable memory. 
     
     
         10 . The system of  claim 9 , wherein the stable memory is flash memory. 
     
     
         11 . The system of  claim 9 , wherein the stable memory is a client terminator's disk. 
     
     
         12 . The system of  claim 9 , wherein the flush request includes a request for the file system to flush the data to the origin file system node. 
     
     
         13 . In a computing system where a data request has been passed between an upstream site and a file service proxy cache node, the file service proxy cache node being an intermediate network node located between the upstream site and the origin file system node, a non-transitory computer-readable storage medium including instructions that, when executed by the file service proxy cache node, performs the steps:
 the file service proxy cache node determining that communication between the file service proxy cache node and the origin file system node has been interrupted;   determining whether an alternate route for communication between the file service proxy cache node and the origin file system node is available;   if the alternate route for communication between the file service proxy cache node and the origin file system node is available:
 obtaining the data to fulfill the data request from the origin file system node over the alternate route for communication between the file service proxy cache node and the origin file system node; and 
 transferring the data to the upstream site with an error code indicating success; and 
   if the alternate route for communication between the file service proxy cache node and the origin file system node is unavailable:
 reporting an error code to the upstream site; and 
 the upstream site determining whether an alternate route for communication between the upstream site and the file system is available. 
   
     
     
         14 . The system of  claim 13  further comprising:
 if the alternate route for communication between the upstream site and the origin file system node is available:
 the upstream site obtaining the data from the origin file system node. 
 
 
     
     
         15 . The system of  claim 13 , further comprising the file service proxy cache node fastpinging the downstream site. 
     
     
         16 . The system of  claim 13 , wherein the upstream site determining whether an alternate route for communication between the upstream site and the origin file system node is available includes:
 checking each node to which the upstream site is connected.   
     
     
         17 . The system of  claim 13 , wherein the upstream site determining whether an alternate route for communication between the upstream site and the origin file system node is available includes forwarding a data request to the origin file system node.