Mailing List Archive

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

Best Regards

--
Martin Wheldon
Greenhills IT Ltd.
Telephone: 01904 238 454

Greenhills IT Ltd. is a limited company registered in England and
Wales.
Company Registration No: 06387214
Registered Offices: 2 Greenhills, Claxton, YORK, North Yorkshire, YO60
7SA



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http://www.linuxvirtualserver.org/

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Re: [lvs-users] Source Hashing scheduler seems to ignore weight [ In reply to ]
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

--
[*] sys4 AG

http://sys4.de, +49 (89) 30 90 46 64, +49 (162) 165 0044
Franziskanerstraße 15, 81669 München

Sitz der Gesellschaft: München, Amtsgericht München: HRB 199263
Vorstand: Patrick Ben Koetter, Marc Schiffbauer
Aufsichtsratsvorsitzender: Florian Kirstein
Re: [lvs-users] Source Hashing scheduler seems to ignore weight [ In reply to ]
On 2014-11-25 12:12, Michael Schwartzkopff wrote:
> 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

Hi Michael,

Thank you for the rapid response.
That is indeed the option I'm looking for. Thank you for pointing me in
the right direction.

Must RTFM in more detail :)

Best Regards

Martin


_______________________________________________
Please read the documentation before posting - it's available at:
http://www.linuxvirtualserver.org/

LinuxVirtualServer.org mailing list - lvs-users@LinuxVirtualServer.org
Send requests to lvs-users-request@LinuxVirtualServer.org
or go to http://lists.graemef.net/mailman/listinfo/lvs-users