The default is 0. This parameter determines whether NTFS generates a short name in the 8.3 (MS-DOS) naming convention for long file names and for file names that contain characters from the extended character set. If the value of this entry is 0, files can have two names: the name that the user specifies and the short name that NTFS generates. If the name that the user specifies follows the 8.3 naming convention, NTFS does not generate a short name.
Changing this value does not change the contents of a file, but it avoids the short-name attribute creation for the file and also changes how NTFS displays and manages the file. For most file servers, the recommended setting is 1.
The default is 0. This parameter disables the processing of write flush commands from clients. If you set the value of this entry to 1, you can improve the server performance and client latency for power-protected servers.
Windows XP client computers only.
Some distributed applications lock parts of a read-only file as synchronization across clients. Such applications require that file-handle caching and collapsing behavior be off for all read-only files. This parameter can be set if such applications will not be run on the system and collapsing behavior can be enabled on the client computer.
Performance Tuning for File Server Workload (SPECsfs2008)
SPECsfs2008 is a file server benchmark suite from Standard Performance Evaluation Corporation that measures file server throughput and response time, providing a standardized method for comparing performance across different vendor platforms. SPECsfs2008 results summarize the server's capabilities with respect to the number of operations that can be handled per second, and the overall latency of the operations.
To ensure accurate results, you should format the data volumes between tests to flush and clean up the working set. For improved performance and scalability, we recommend that you partition client data over multiple data volumes. The networking, storage, and interrupt affinity sections of this paper contain additional tuning information that might apply to specific hardware.
Registry-Tuning Parameters for NFS Server
You can tune the following registry parameters to enhance the performance of NFS servers:
NTttcp is a Winsock-based port of ttcp to Windows. It helps measure network driver performance and throughput on different network topologies and hardware setups. It provides the customer a multithreaded, asynchronous performance workload for measuring achievable data transfer rate on an existing network setup. For more information, see “Resources” later in this guide.
Options include the following:
A single thread should be sufficient for optimal throughput.
Multiple threads are required only for single to many clients.
Posting enough user receive buffers (by increasing the value passed to the -a option) reduces TCP copying.
You should not excessively post user receive buffers because the first ones that are posted would return before you need to use other buffers.
Make sure that you enable all offloading features.
TCP/IP Window Size
For 1-GB adapters, the settings shown in Table 11 should provide you good throughput because NTttcp sets the default TCP window size to 64 K through a specific socket option (SO_RCVBUF) for the connection. This provides good performance on a low-latency network. In contrast, for high-latency networks or for 10-GB adapters, NTttcp’s default TCP window size value yields less than optimal performance. In both cases, you must adjust the TCP window size to allow for the larger bandwidth delay product. You can statically set the TCP window size to a large value by using the -rb option. This option disables TCP Window Auto-Tuning, and we recommend its use only if the user fully understands the resultant change in TCP/IP behavior. By default, the TCP window size is set at a sufficient value and adjusts only under heavy load or over high-latency links.
Receive-Side Scaling (RSS)
Windows Server 2008 R2 supports RSS out of the box. RSS enables multiple DPCs to be scheduled and executed on concurrent processors, which improves scalability and performance for receive-intensive scenarios that have fewer networking adapters than available processors. Note that, because of hardware limitations on some adapters and other functionality constraints, not all adapters can support concurrently processing DPCs on all processors on the server. DPCs are also not scheduled on hyperthreading processors because of an adverse effect on performance. Therefore, DPCs in RSS are scheduled only on logical and physical processors regardless of how many cores or sockets are on the server.