[OpenIndiana-discuss] mbuffer connection refused on varius ports ... what to try

[Harry Putnam]

James Carlson via openindiana-discuss
<openindiana-discuss at openindiana.org> writes:

> On 03/27/17 04:40, Harry Putnam wrote:
>> My rendition:
>> 
>> zfs send p0/vb/vm at 170326_1 |tamp|mbuffer -s 128k -m1000m -0
>> recv-host:31337 | mbuffer -s 128k -m 1999m -I 31337 |tamp -d |
>> zfs recv -vF p0/vb/vm
>
> That makes no sense at all.  The mbuffer utility doesn't produce usable
> output on stdout when given a host name to connect to, and doesn't read
> from stdin when given a port number.  So piping from one to the other is
> confounding.  And running both on one host isn't logical.  I don't see
> what you're trying to do there.

Not sure where you got the notion that I'm trying to run both
operations on the same host... probably due to some idiocy in my
formulation.

> If you plan to use mbuffer between two systems, you have to run the
> receiver on one host, and the sender on the other.

I did mention in my post that I had tried by running receiver first on
remote host.  It failed too with the error posted.

Jamec C's excellent advice follows:

> Start the receiver first.

> If you see "connection refused" warnings, then it's time to start
> looking at:
>
>   - Is the port actually open on the receiver's side when the mbuffer
>     utility?  Use "netstat -na" to look for it on the receiver after
>     starting up mbuffer on that system.
>
>   - Are you actually connecting to the host you think you are?  Make
>     sure that "recv-host" actually resolves to a valid IP address on
>     the receiving system, as viewed by the sender.  Typing
>     "host recv-host" on the sender's side can help confirm that.

With that advice in mind I simplified my commands as so:

,----
|  On RECV-HOST:
|   mbuffer -s 128k -m19m -I 31337 |zfs recv -vF POOL/fs
| 
|      Checking netstat -na |grep 31337 ... shows it is listening.
|       (Thx for that good diagnostic technique)
| 
|  On SEND-HOST
|   zfs send -v POOL/fs at snap | mbuffer -s 128k -m 18m -0 RECV-HOST -I 31337
| 
| Reports:
| 
|    send from @ to rpool/merc at 170327 estimated size is 10.1M
|    total estimated size is 10.1M
|    TIME        SENT   SNAPSHOT
|  
|    summary: 11.1 MiByte in  0.5 sec - average of 24.1 MiB/s
`----

Yippee .. it worked.

Thank you James C for persisting even when my feeble attempts look
foolish and inept to you.

The test had very small data but succeeded, so:

I now have a working example to try to work `tamp' into the commands
for when sending much larger amounts of data.