Fwd: backing up to a Drobo CIFS VFS: Error -11 sending data on socket to server, Bufferbloat?

Robert Kudyba rkudyba at fordham.edu
Wed May 31 01:00:54 UTC 2017

> The problem appears to be firewall related because I am seeing ICMP
> Dest Unreachable responses to an SMB Write&X Response (frame 5816 and
> 5817).
> Do a search on tcp.port == 42166 and you will see the response and
> then a DEST Unreachable, then a retransmit in 120 seconds and another
> DEST Unreachable etc.
> However, there is also another SMB session on tcp.port == 53858 where
> the Drobo is returning INVALID handle on the WRITES ... which seems to
> be the fundamental problem.
> However, stuff is missing from the capture.
> This session seems to indicate the problem: tcp.port == 53860
> There are a bunch of writes, but eventually the Windows fills up and
> the Drobo stops responding at the TCP layer and eventually one party
> or other RSTs the connection. Looks like a Drobo problem to me.

Just looping back to this. Drobo says we are past our support period
and won't research a fix. They blame CIFS and large files, and I do
see an old bug from 2007

Is this something that would ever get fixed?

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