windows 2000: slow file copy from windows 2000 to SAMBA

[Coupal, Chris ISC]

Greetings,

I have a interesting problem copying large files from a Windows2000 server
to a SAMBA share. The copy takes extremely long. For example, a 600K file
takes in excess of 40 seconds. Initially, we had the problem copy the file
to NT 4 machines as well, but we fixed it with the following work around
which explains the problem well:

Is there a way we can apply the same "FIX" to samba?

Regards,
Chris



		Q279282 - Slow File Write from Windows 2000 to Windows NT
4.0 Server 
		 Excerpt from this page:The file-copy write process from a
Windows 2000 Professional-based computer to a Windows NT 4.0 Server-based
computer may take up to four times longer than reading the same files from
Windows NT Server. The Windows 2000 workstation redire(size 9780 bytes,
updated 4/11/2001 4:19:00 AM GMT 

		Slow File Write from Windows 2000 to Windows NT 4.0 Server 

	
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		The information in this article applies to:

		Microsoft Windows NT Server version 4.0 
		Microsoft Windows 2000 Advanced Server 
		Microsoft Windows 2000 Datacenter Server 
		Microsoft Windows 2000 Professional 
		Microsoft Windows 2000 Server

	
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		IMPORTANT: This article contains information about editing
the registry. Before you edit the registry, make sure you understand how to
restore it if a problem occurs. For information about how to do this, view
the "Restoring the Registry" Help topic in Regedit.exe or the "Restoring a
Registry Key" Help topic in Regedt32.exe.


		SYMPTOMS
		The file-copy write process from a Windows 2000
Professional-based computer to a Windows NT 4.0 Server-based computer may
take up to four times longer than reading the same files from Windows NT
Server. 



		CAUSE
		The Windows 2000 workstation redirector does not support RAW
SMB mode. Instead, Windows 2000 uses Large File (CAP_LARGE_FILE) support,
which is just as fast. However, not all earlier operating systems implement
Large File support. For example, Windows NT 4.0 has Large File Read support,
but not Large File Write support. 



		RESOLUTION
		WARNING: Using Registry Editor incorrectly can cause serious
problems that may require you to reinstall your operating system. Microsoft
cannot guarantee that problems resulting from the incorrect use of Registry
Editor can be solved. Use Registry Editor at your own risk.

		For information about how to edit the registry, view the
"Changing Keys and Values" Help topic in Registry Editor (Regedit.exe) or
the "Add and Delete Information in the Registry" and "Edit Registry Data"
Help topics in Regedt32.exe. Note that you should back up the registry
before you edit it. If you are running Windows NT or Windows 2000, you
should also update your Emergency Repair Disk (ERD).

		To work around this performance issue, make the following
registry change on the Windows NT 4.0-based server: 

		Start Registry Editor (Regedt32.exe).


		Locate and click the following key in the registry:


	
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\lanmanserver\parameters

		On the Edit menu, click Add Value, and then add the
following registry value:


		Value Name: SizReqBuf
		Data Type: DWORD Value
		Radix: Decimal
		Value: 65535 
		Quit Registry Editor.


		Restart the server.


		After you make this change, the performance of the write
process is approximately the same as a read operation between the two
computers. 

		Note that the SizReqBuf value controls the buffer size for
CORE SMB requests. Setting it to 64 KB has approximately the same effect as
Large Write support, which uses 60-KB buffers. 

		NOTE: This adjustment causes the server services to use more
memory. 



		MORE INFORMATION
		Windows 2000 read operations are fast because they use the
SMB Large Read capability of Windows NT Server (CAP_LARGE_READX). Windows NT
Server does not support CAP_LARGE_WRITEX. For more information, see the
"Common Internet File System (CIFS)" specification at the following
Microsoft Web site: 

	
http://msdn.microsoft.com/workshop/networking/cifs/default.asp
		File-copy operations from Windows 2000 to Windows 2000 work
quickly. They use CAP_LARGE_READX and CAP_LARGE_WRITEX capabilities to send
files in 60-KB portions. Also, file-copy operations from Windows NT to
Windows NT work quickly. They use CAP_RAW_MODE to send files in 64-KB
portions. For additional information, click the article numbers below to
view the articles in the Microsoft Knowledge Base: 
		Q99234 History of SizeReqBuf Changes 
		Q223140 SMB Size Negotiation When Copying Files with Windows
NT Explorer 

		Additional query words: 

		Keywords : kbenv 
		Issue type : kbprb 
		Technology : kbWinNTsearch kbwin2000AdvServSearch
kbwin2000DataServSearch kbWinNTSsearch kbwin2000Ssearch kbwin2000ProSearch
kbExchange400 kbWinAdvServSearch kbWinDataServSearch


Chris Coupal
EDS Canada
Information Services Corporation of Saskatchewan
(306) 787-0126
chris.coupal at eds.com