On 02:46 PM 3/20/2006, Tom Harms wrote:
>[snip: Accessing application files on 2003 server is fast for the first PC but slow for the second PC. Accessing files on XP seems to be fine regardless of the order]
>
>When doing a search in my app, I've found that the first PC (call it PC#1) to attach to the share gets relatively good performance (2 second response). The second PC (PC#2) then slows way down (7 second response). Note that the results are the same regardless of which actual PC I use as PC#1 and PC#2 - it's the order and not something about the actual PC that changes the performance.
>
>My ethereal trace showed me that the extra slowdown on PC#2 is caused by lots and lots of extra SMB Packets. (PC#1 has around 20% SMB packets and the rest general TCP/IP, whereas PC#2 has around 80% SMB packets.
>Around 4MB of extra data passing back and forth.). The surplus seems to all (or almost all) be of the form
>
> Read Andx Request
> Read Andx Response
>
>At one point there are around 22,000 consecutive such transactions with almost nothing else.
Perhaps something to do with file locking or oplocks?
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/cifs/protocol/cifs_oplock_file_locking.asp
Worth a look
hsb