[Samba] Increase data length for SMB2 write and read requests for Windows 10 clients

Jeremy Allison jra at samba.org
Tue Aug 22 16:30:35 UTC 2023

On Tue, Aug 22, 2023 at 06:15:39PM +0200, Ralph Boehme wrote:
>On 8/22/23 18:02, Jeremy Allison wrote:
>>On Tue, Aug 22, 2023 at 08:50:03AM +0200, Ralph Boehme wrote:
>>>I don't get it. Iirc 8 MB is the default max io size the kernel 
>>>client will use which is also, iirc, the limit of the protocol.
>>Don't get what ? The FastCopy.exe above is using 8MB write sizes.
>sure, so? FastCopy.exe uses 8 meg, Explorer and Robocopy use a smaller 
>IO size. Or am I missing something?

Ah, I see the disconnect. I was assuming the Win RDR was chopping
up large IO sizes into 1MB chunks, and a registry entry was needed
to stop it doing that.

You're saying this is completely driven by the calling application,
and the write sizes passed down to the RDR are kept (unless they're
greater than 8MB, in which case they're split up).

I don't write Win32 code anymore, so someone who does will need
to check :-).

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