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I have a NAS server with OpenSolaris and kernel-based CIFS/Samba share and I get these weird results when working with it from different computers over the Gigabit LAN:

  1. Read speed is blazing fast and almost saturates 1GB LAN (90-100 MB/sec)
  2. Write from Macbook Pro (OS X 10.6.4) is fast (60 MB/sec)
  3. Write from Win7 is slow (no more than 15 MB/sec, sometimes 2-3 MB/sec) and buggy (it stops/interrupts other TCP/IP connections e.g. web browser; and, vice versa, working with other network applications while copying a file to a remote SMB share often makes Windows "lose" the network share and abort copying).
  4. Write from Win7 using FAR Manager (third-party file manager for Windows) with "Use system copy routine = No" is fast (60 MB/sec) and flawless
  5. Write from Win7 using FAR Manager with "Use system copy routine = Yes" is slow and buggy (same as using Explorer, see p.3)

The problem is definitely related to the native Win7 copy routine (as FAR Manager in compatibility mode writes to SMB shares without any problems). I tried to disable SMB2 with

HKLM\SYSTEM\CurrentControlSet\Services\LanmanServer\Parameters\SMB2 = 0

and running this in command line:

sc config lanmanworkstation depend= bowser/mrxsmb10/nsi
sc config mrxsmb20 start= disabled

but it didn't give anything. I also tried to disable OpLocks with:

HKLM\SYSTEM\CurrentControlSet\services\LanmanServer\Parameters\EnableOpLocks = 0
HKLM\SYSTEM\CurrentControlSet\services\mrxsmb\Parameters\OplocksDisabled = 1

and that didn't help either.

Any advices?

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Just a shot in the dark, could it be a conflict with the TCP chimney offload? blogs.msdn.com/b/psssql/archive/2008/10/01/… Disable with "netsh int tcp set global chimney=disable" –  Chris Smith Aug 17 '11 at 6:34

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