What is maximum SMB2 IOCTL(FSCTL_GET_SHADOW_COPY) response size.

Volker Lendecke Volker.Lendecke at SerNet.DE
Tue Jan 20 00:39:59 MST 2015

On Mon, Jan 19, 2015 at 02:22:14PM -0800, Hemanth Thummala wrote:
> Thanks all for your responses.
> As Stefan(metze) and Richard pointed out, this looks like SMB2.0 limitation
> to me. In negotiate process, max trans size is limited to 64K if we are not
> supporting large MTU or multi credits.
> I have tried modifying this max trans size from 64KB to 256KB. Could see
> that it negotiating 256K with client. But there is no difference in client
> behavior when trying to send huge response(~90K). Not sure if this is
> SMB2.0 client's limitation. Or we might need to port the multi-credits and
> large MTU support to really support huge response buffer size.
> If there is a clear limitation for smb2.0 protocol, we might probably need
> to truncate the response to 64K.

Not sure if that makes sense to test, but what happens
with Win7->Win7 without the DisableLargeMTU setting in this


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