[lvs-users] Source Hashing scheduler seems to ignore weight

[Michael Schwartzkopff]

Am Dienstag, 25. November 2014, 11:50:28 schrieb Martin Wheldon:
> Hi,
> 
> We have been running a LVS cluster for many years using the WLC
> scheduler which works fantastically well.
> Thank you everyone involved in the project.
> 
> However we now have a requirement to also run a cluster using the
> Source Hashing scheduler, which is
> giving us a few problems.
> 
> We would like to limit the number of connections to a real server and
> it seems this should be possible
> by setting the weight at a appropriate level.
> 
> http://kb.linuxvirtualserver.org/wiki/Source_Hashing_Scheduling
> 
> The snippet below seems to indicate that there may be a bug in that the
> number of active connections
> for each of the real servers below is well beyond the expected 800.
> That or I've misunderstood
> the documentation.
> 
> IP Virtual Server version 1.2.1 (size=4096)
> Prot LocalAddress:Port Scheduler Flags
>    -> RemoteAddress:Port           Forward Weight ActiveConn InActConn
> FWM  3128 sh (sh-fallback)
> ...
> ...
> ...
>    -> 10.1.5.152:0                 Masq    400    3023       6115
>    -> 10.1.5.163:0                 Masq    400    1455       5288
>    -> 10.1.5.172:0                 Masq    0      1071       3306
>    -> 10.1.5.190:0                 Masq    400    1350       5267
>    -> 10.1.6.241:0                 Masq    400    1046       3190
>    -> 10.1.6.242:0                 Masq    400    3231       5512
>    -> 10.1.6.245:0                 Masq    400    1309       3604
> ...
> ...
> 
> My questions being has anyone else seen/experienced this issue and if
> so how did you work round/fix it?

hi,

as fars as I understood 

http://www.linuxvirtualserver.org/docs/scheduling.html

there is no weight involved in the source-hash scheduler. Any by the way: A 
"weight" is NOT the maximum number of connections ipvs will forward to that 
real server. In weight-respecting schedulers it is the relative weigth in 
respect to the sum over all weigth of all real servers.

If you want to limit the numer of connetions, see "man ipvs" and look for the 
"limit" section. As far as I remember it is the -y option op ipvsadm.

Best Regards
-- 
Mit freundlichen Grüßen,

Michael Schwartzkopff

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