Re: Re: NFS synchronization problems on Beowulf cluster

[Peter Staubach <staubach@redhat.com>]

Mario Storti wrote:

>Peter Staubach <staubach <at> redhat.com> writes:
>
>  
>
>>Can you get a raw tethereal capture file which shows the issue?  Perhaps
>>a capture which includes reading the original contents of the file and
>>then reading it again after the file is modified on the server or by
>>another client?  Perhaps from that we can get some clues as to where the
>>problem might be.
>>    
>>
>
>OK. Good idea. I added a line with `#jaja12' to my file `~/.bashrc'
>and verified that all nodes see the change. Then I modify the line
>with Emacs in the server to `#jaja13' and svae, then to `#jaja14' and
>save, and to `#jaja15'. Some nodes acknowledge the change but others
>not. If I do a `parallel grep' I obtain the following
>
>================================================================
>[mstorti@aquiles ~]$ pdsh -a 'grep jaja ~/.bashrc'
>node2: # jaja12
>node1: # jaja15
>node9: # jaja15
>node10: # jaja14
>node11: # jaja12
>node13: # jaja15
>node20: # jaja15
>node3: # jaja15
>node17: # jaja12
>node4: # jaja15
>node7: # jaja12
>node8: # jaja15
>node18: # jaja15
>node6: # jaja12
>node14: # jaja14
>node12: # jaja15
>node16: # jaja14
>node5: # jaja15
>node19: # jaja14
>node15: # jaja15
>[mstorti@aquiles ~]$ 
>================================================================
>
>So I choose for instance `node2' which has still the "# jaja12"
>string. Then 
>
>* I open a shell in node2,  
>* Launch a `tethereal' filtering the
>        communication between the server (192.168.0.201) and node2
>        (192.168.0.2).
>* I do a grep in node2
>
>    [mstorti@node2 ~]$ grep jaja .bashrc
>    # jaja12
>    [mstorti@node2 ~]$ 
>
>* and I close the `tethereal'. 
>
>What I obtain is the following:
>
>================================================================
>[root@aquiles ~]# tethereal -i eth0 host aquiles and host node2
>Capturing on eth0
>  0.000000  192.168.0.2 -> 192.168.0.201 UDP Source port: 32769  Destination
>port: 8649
>  2.490445 192.168.0.201 -> 192.168.0.2  Rlogin Data: g
>  2.490548  192.168.0.2 -> 192.168.0.201 Rlogin Data: g
>  2.490567 192.168.0.201 -> 192.168.0.2  Rlogin Data: rep jaja .bashrc\n
>  2.490794  192.168.0.2 -> 192.168.0.201 Rlogin Data: rep jaja .bashrc\r\n
>  2.491546  192.168.0.2 -> 192.168.0.201 NFS V3 GETATTR Call, FH:0x76120002
>  2.491597 192.168.0.201 -> 192.168.0.2  NFS V3 GETATTR Reply (Call In 6)
>  2.491669  192.168.0.2 -> 192.168.0.201 TCP 1023 > nfs [ACK] Seq=108 Ack=116
>Win=32645 Len=0 TSV=612612 TSER=27245753
>  2.491676  192.168.0.2 -> 192.168.0.201 NFS V3 GETATTR Call, FH:0xf8ea8c0a
>  2.491701 192.168.0.201 -> 192.168.0.2  NFS V3 GETATTR Reply (Call In 9)
>  2.529519  192.168.0.2 -> 192.168.0.201 TCP 1023 > nfs [ACK] Seq=216 Ack=232
>Win=32674 Len=0 TSV=612616 TSER=27245753
>  2.536043 192.168.0.201 -> 192.168.0.2  TCP 1023 > login [ACK] Seq=18 Ack=19
>Win=1460 Len=0 TSV=27245757 TSER=612612
>  2.536144  192.168.0.2 -> 192.168.0.201 Rlogin Data: # jaja12\r\n[mstorti@node2
>~]$ 
>  2.539333 192.168.0.201 -> 192.168.0.2  TCP 1023 > login [ACK] Seq=18 Ack=48
>Win=1460 Len=0 TSV=27245757 TSER=612616
>  7.549413  192.168.0.2 -> 192.168.0.201 UDP Source port: 32769  Destination
>port: 8649
>  7.549424  192.168.0.2 -> 192.168.0.201 UDP Source port: 32769  Destination
>port: 8649
>  7.549428  192.168.0.2 -> 192.168.0.201 UDP Source port: 32769  Destination
>port: 8649
>  7.549431  192.168.0.2 -> 192.168.0.201 UDP Source port: 32769  Destination
>port: 8649
>  7.549435  192.168.0.2 -> 192.168.0.201 UDP Source port: 32769  Destination
>port: 8649
>  7.549438  192.168.0.2 -> 192.168.0.201 UDP Source port: 32769  Destination
>port: 8649
>20 packets captured
>[root@aquiles ~]# 
>================================================================
>
>Do you see something in there? I am studying it, but I didn't know
>enough of NFS for understaing it yet.
>

Actually, what I asked about was a "raw capture file".  I think that
the values returned in the GETATTR calls may be interesting.  To see
them, we need more then just the summary lines.

Can you do this again, but have tethereal capture into a file (via
the -w option) and then attach that file to a note to me or this list,
please?

    Thanx...

       ps


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