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Troubleshooting

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BranchCache doesn’t function

Client performance counters show no bytes coming from the cache when accessing BranchCache enabled servers. Branch office clients can still download content from the servers.

Follow the steps in Verifying end-to-end deployment with performance counters earlier in this document. Run the performance monitor on both client computers.

Symptom: BytesAddedToCache does not increase on the first client when accessing the BranchCache-enabled server.

  • The client computer may be retrieving content from the Internet Explorer cache. Be sure to clear the IE cache by selecting Internet Options from the Tools menu, and clicking Delete.

  • Ensure that BranchCache is enabled on the first client using the netsh branchcache show status command.

  • If attempting to access a file share, verify that the latency between the client and server is higher than the minimum threshold.

  • Ensure that the BranchCache feature is installed on the server and is enabled for the protocol under test.

  • Check that the peerdistsvc server has started on both the client and the server.

  • An intermediate proxy may alter the HTTP request coming from the client. Verify that the proxy does not modify the ACCEPT-ENCODING HTTP header.

Note

ISA 2006 may alter this header. To configure ISA 2006 to function correctly with BranchCache, disable the compression filter.

  • An intermediate proxy may downgrade the outgoing request from HTTP 1.1 to HTTP 1.0.

  • If the symptom is specific to file traffic, ensure that the file is not in the transparent cache. Transparent cache is a secondary cache where the file is stored in addition to the BranchCache. Storing the file in the transparent cache enables subsequent reads of the file to be satisfied locally improving end-user response times and savings on WAN bandwidth. To delete transparently cached data, search for Offline Files applet in Control Panel. Click the Disk Usage tab, and then click Delete Temporary Files. Note that this will not clear the BranchCache cache.

Symptom: BytesAddedToCache does increase on the first client when accessing the BranchCache enabled server. BytesFromCache does not increase on the second client when accessing the BranchCache enabled server. Deployment is Distributed Cache mode.

  • Ensure that BranchCache is enabled and that both clients are configured to use the same caching mode using the netsh branchcache show status command.

  • Ensure that the correct firewall exceptions are set on both clients using the netsh branchcache show status command.

  • Ensure that both clients are connected to the same subnet using the ipconfig command.

  • Make sure the client cache is not full using netsh branchcache show status ALL.

Symptom: BytesAddedToCache does increase on the first client when accessing the BranchCache enabled server. BytesFromCache does not increase on the second client when accessing the BranchCache enabled server. Deployment is Hosted Cache mode.

  • Ensure that BranchCache is enabled and that both clients are configured to use the same caching mode using the netsh branchcache show status command.

  • Verify basic connectivity from both client computers to the Hosted Cache using the ping command.

  • Ensure that the correct firewall exceptions are set on both clients using the netsh branchcache show status command.

  • Ensure that the correct firewall exceptions are set on the Hosted Cache server using the netsh branchcache show status command.

  • Ensure that the certificate is properly installed and bound to port 443 on the Hosted Cache computer.

Symptom: Netsh shows BranchCache firewall rules have not been set, even though they have been configured using Group Policy.

Netsh checks the predefined BranchCache firewall rule group. If you have not enabled the default exceptions defined for BranchCache on Windows 7, Netsh will not report your configuration correctly. This is likely to happen if you defined firewall rules for clients using Group Policy and you defined the Group Policy object on a computer running an operating system older than Windows 7 or Windows Server 2008 R2 (which would not have the BranchCache firewall rule group). Note that this does not mean BranchCache will not function.

BranchCache and client performance

Symptom: A client computer is running slowly. Is BranchCache at fault?

Many computers drawing large amounts of content from one client in a short time period may impact desktop performance.

  • Use performance monitor to check for high service rates to peers. Examine BytesServedToPeers relative to BytesFromCache and BytesFromServer.

  • The BranchCache service runs isolated in its own service host. Examine the CPU and memory consumption of the service host process housing the branch caching service.

  • Sustained high rates of service to peers may be evidence of a configuration problem in the branch office. Check to make sure that the other clients in the branch office are capable of service data.

  • Clear the cache on the affected client using the netsh branchcache flush command or reduce the cache size on the affected client.

Application failures

Symptom: A page fails to load or a share cannot be accessed.

When BranchCache is unable to retrieve data from a peer or from the Hosted Cache, the upper layer protocol will return to the server for content. If a failure occurs in the Branch Caching component, the upper layer protocol should seamlessly download content from the server. No BranchCache misconfiguration or failure should prevent the display of a webpage or connection to a share. If a failure does occur, use the Network Diagnostic Framework Diagnose button provided by Windows Explorer or Internet Explorer.

Symptom: The client computer is unable to access the file share even when connected to the server.

  • If the client computer is unable to access a file share on the server due to the error Offline (network disconnected), reboot the client computer and access the share again.

  • If the client computer is unable to access a file share on the server due to the error Offline (slow connection), delete the temporarily cached data, reboot the computer and access the share. To delete temporarily cached data (the same as the transparent cache described above), search for Offline Files applet in Control Panel. Click the Disk Usage tab, and then click Delete Temporary Files.