[Spread-users] Spread Retransmission Help

Matt Garman matthew.garman at gmail.com
Mon Oct 7 12:31:22 EDT 2013


Just throwing out ideas: is it possible you have a separate network
problem?  Maybe a bad cable somewhere or a network device that's about to
die?  Is the overall load of your network very high?

You could use something like multicast (not Spread multicast, just raw UDP
multicast) to see if you're getting packet drops in your network.  While
the UDP spec obviously allows for packet drops, on a wired LAN in the same
physical location with low network load, you should virtually never see
actual dropped packets.

Maybe even start more simply and look at interface statistics for all the
devices (switches, routers, servers) on your network and see if you have
packet drops.




On Mon, Oct 7, 2013 at 11:22 AM, Lane Matthew <Matthew.Lane at external.eni.com
> wrote:

> Thanks for the quick replies.
>
> I have tested using spsend and sprecv as suggested. What I have found is
> that the number of 'missed' varies each time I run the send. Sometimes it
> is 0; other times it is 90%.
>
> > spsend -a 225.1.2.3 -n 100
> Checking (225.1.2.3, 4444). Each burst has 100 packets, 1024 bytes each
> with 10 msec delay in between, for a total of 100 packets
> total time is (0,31000), with 0 problems
>
> > sprecv -a 225.1.2.3 -d
> -------
>  --> count is 30, i is 28, missed 2 total missed 2, corrupt 0
>  --> count is 73, i is 39, missed 34 total missed 36, corrupt 0
>  --> count is 94, i is 82, missed 12 total missed 48, corrupt 0
> -------
> Report: total packets 100, total missed 48, total corrupted 0
> -------
>
> Thanks
> Matthew Lane
>
> -----Original Message-----
> From: John Schultz [mailto:jschultz at spreadconcepts.com]
> Sent: 07 October 2013 16:27
> To: Lane Matthew
> Cc: spread-users at lists.spread.org
> Subject: Re: [Spread-users] Spread Retransmission Help
>
> Given that subnet mask, that is the proper broadcast address.  If this
> network is more complicated than a single switch or router, then it might
> be that broadcast is turned off or not working for parts of it.  You could
> also try using a multicast address rather than the broadcast address to see
> if that works better.
>
> Are you sure there are no firewalls interfering with any of the ports
> (14803 UDP and 14804 UDP)?
>
> As Yair suggested you could build and use the spsend and sprecv programs
> to try to find why your loss is so significant.
>
> Cheers!
>
> -----
> John Lane Schultz
> Spread Concepts LLC
> Cell: 443 838 2200
>
> On Oct 7, 2013, at 11:02 AM, Lane Matthew wrote:
>
> Thanks.
>
> I thought this too so I verified the broadcast address using the IP and
> subnet mask. Subnet Mask=255.255.254.0 for all servers. Looking online,
> 10.151.141.255 is the network broadcast address for this subnet. Have I
> misunderstood something in the setup?
>
> Thanks
>
> Matthew Lane
>
>
> -----Original Message-----
> From: John Schultz [mailto:jschultz at spreadconcepts.com]
> Sent: 07 October 2013 15:49
> To: Lane Matthew
> Cc: spread-users at lists.spread.org
> Subject: Re: [Spread-users] Spread Retransmission Help
>
> I think your network addresses are wrong.
>
> Your segment broadcast address is 10.151.141.255 while your machines are
> sitting in the 10.151.140 network.  That probably isn't right, so your
> segment address probably isn't working at all and Spread is working hard to
> overcome that.
>
> Cheers!
>
> -----
> John Lane Schultz
> Spread Concepts LLC
> Cell: 443 838 2200
>
> On Oct 7, 2013, at 10:38 AM, Lane Matthew wrote:
>
> Hi,
>
> Whilst looking at the spread logs; I noticed verion high retans numbers.
> Is this expected or does it suggest I have a problem? If the latter; how
> would you suggest I could go about indentifying what the problem could be?
>
>
> Config
>
> Spread_Segment  10.151.141.255:14803  {
>        SERVER1 10.151.140.236
>        SERVER2 10.151.140.237
>        SERVER3 10.151.140.234
>        SERVER4 10.151.140.235
> }
> Spread Logs
> ============================
> Status at SERVER4 V 4.00. 0 (state 1, gstate 1) after 4641117 seconds :
> Membership  :  4  procs in 1 segments, leader is SERVER1
> rounds   : 24279316     tok_hurry : 19921464    memb change:      21
> sent pack: 24535749     recv pack : 77414263    retrans    : 8423199
> u retrans: 6694629      s retrans : 1728570     b retrans  :       0
> My_aru   : 15433449     Aru       : 15433449    Highest seq: 15433449
> Sessions :     116      Groups    :    1977     Window     :      60
> Deliver M: 57102298     Deliver Pk: 89528715    Pers Window:      15
> Delta Mes:    1233      Delta Pack:     215     Delta sec  :      25
> ==================================
>
> Monitor>
> ============================
> Status at SERVER3 V 4.00. 0 (state 1, gstate 1) after 2659181 seconds :
> Membership  :  4  procs in 1 segments, leader is SERVER1
> rounds   : 24279315     tok_hurry : 11045561    memb change:      14
> sent pack: 13845399     recv pack : 40335734    retrans    : 2957258
> u retrans: 1117748      s retrans : 1839510     b retrans  :       0
> My_aru   : 15433449     Aru       : 15433449    Highest seq: 15433449
> Sessions :      53      Groups    :    1977     Window     :      60
> Deliver M: 29916378     Deliver Pk: 47580732    Pers Window:      15
> Delta Mes: -27185920    Delta Pack:       0     Delta sec  : -1981936
> ==================================
>
> Monitor>
> ============================
> Status at SERVER1 V 4.00. 0 (state 1, gstate 1) after 3822591 seconds :
> Membership  :  4  procs in 1 segments, leader is SERVER1
> rounds   : 24279316     tok_hurry : 18360366    memb change:      14
> sent pack: 14094574     recv pack : 72830765    retrans    : 6315107
> u retrans: 3723218      s retrans : 2591889     b retrans  :       0
> My_aru   : 15433449     Aru       : 15433449    Highest seq: 15433449
> Sessions :      81      Groups    :    1977     Window     :      60
> Deliver M: 47437911     Deliver Pk: 74928112    Pers Window:      15
> Delta Mes: 17521533     Delta Pack:       0     Delta sec  : 1163410
> ==================================
>
> Monitor>
> ============================
> Status at SERVER2 V 4.00. 0 (state 1, gstate 1) after 4641102 seconds :
> Membership  :  4  procs in 1 segments, leader is SERVER1
> rounds   : 24279315     tok_hurry : 19920799    memb change:      16
> sent pack: 16699063     recv pack : 81794705    retrans    : 10967659
> u retrans: 7755320      s retrans : 3212339     b retrans  :       0
> My_aru   : 15433449     Aru       : 15433449    Highest seq: 15433449
> Sessions :      72      Groups    :    1977     Window     :      60
> Deliver M: 57101208     Deliver Pk: 89523128    Pers Window:      15
> Delta Mes: 9663297      Delta Pack:       0     Delta sec  :  818511
> ==================================
>
>
>
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