LVS
lvs-users
Google
 
Web LinuxVirtualServer.org

Re: [lvs-users] Question on SH scheduler

To: "LinuxVirtualServer.org users mailing list." <lvs-users@xxxxxxxxxxxxxxxxxxxxxx>
Subject: Re: [lvs-users] Question on SH scheduler
Cc: Alexander Holler <holler@xxxxxxxxxxxxx>
From: Simon Horman <horms@xxxxxxxxxxxx>
Date: Tue, 28 Feb 2012 18:35:49 +0900
On Tue, Feb 28, 2012 at 02:06:12PM +0530, krishna prasad wrote:
> Hi Simon,
> 
> On Tue, Feb 28, 2012 at 12:42 PM, Simon Horman <horms@xxxxxxxxxxxx> wrote:
> 
> > On Tue, Feb 28, 2012 at 11:36:11AM +0530, krishna prasad wrote:
> > > On Tue, Feb 28, 2012 at 11:18 AM, Alexander Holler <holler@xxxxxxxxxxxxx
> > >wrote:
> > >
> > > > Am 28.02.2012 06:35, schrieb krishna prasad:
> > > >
> > > >> On Tue, Feb 28, 2012 at 10:44 AM, Alexander Holler<
> > holler@xxxxxxxxxxxxx>*
> > > >> *wrote:
> > > >>
> > > >>  Am 28.02.2012 06:11, schrieb krishna prasad:
> > > >>>
> > > >>>  On Tue, Feb 28, 2012 at 10:04 AM, Alexander Holler<
> > holler@xxxxxxxxxxxxx
> > > >>> >*
> > > >>>
> > > >>>> *wrote:
> > > >>>>
> > > >>>>
> > > >>>>  Hello,
> > > >>>>
> > > >>>>>
> > > >>>>> Am 28.02.2012 04:26, schrieb krishna prasad:
> > > >>>>>
> > > >>>>>
> > > >>>>>     But I strongly think that it it good to have IP+port hashing,
> > for
> > > >>>>> cases
> > > >>>>>
> > > >>>>>  where multiple clients run on single host, in this case
> > > >>>>>> the connections have same IP but different port. In this case
> > also the
> > > >>>>>> same
> > > >>>>>> is desirable,i.e same client to the same real-server.
> > > >>>>>> This may not make a real use case for web world, but a strong
> > case for
> > > >>>>>> non-web deployments like in telecom.I know LVS is increasingly
> > used in
> > > >>>>>> other than web services.
> > > >>>>>>
> > > >>>>>>
> > > >>>>>>  What should be the use case for this? Source ports are almost
> > always
> > > >>>>> choosen randomly, so you woould get the same results as balancing
> > > >>>>> randomly.
> > > >>>>>
> > > >>>>>
> > > >>>>>  Not necessarily,I came across few implementations where client
> > port is
> > > >>>> fixed (they bind() port while creating socket), but I agree that
> > most of
> > > >>>>
> > > >>>>
> > > >>> Sure.
> > > >>>
> > > >>>
> > > >>>  the times source port is random.
> > > >>>
> > > >>>> The good approach would be LVS to provide options  for IP+port or
> > just
> > > >>>> IP
> > > >>>> hashing.
> > > >>>>
> > > >>>>
> > > >>> But I still miss the use case. If the client always does come with
> > the
> > > >>> same port, it doesn't make a difference if the port is used too for
> > > >>> hashing
> > > >>> or just the IP.
> > > >>>
> > > >>>
> > > >> Oh..Sorry, I should have been clear.
> > > >> Here is the use case: I have a client (from out side it looks like a
> > piza
> > > >> box, but internally it has many CPU..something like blade server/ATCA)
> > > >> which initiates TCP/SCTP connections with same IP address but with
> > > >> different Port.
> > > >> So if I use SH, all these connections (potentially this client can
> > > >> initiate
> > > >> as many as 40 connections) will land on a same real server which may
> > not
> > > >> be
> > > >> what we wanted. we wanted the connections to be balanced (based on
> > > >> IP+port)
> > > >> across all the real servers. Does it make sense?
> > > >>
> > > >
> > > > Hmm, if it comes to a few thousand different ports, it would, but not
> > for
> > > > 40 (imho). ;)
> > > >
> > > > Anyway, this discussion should be held at the ML, not private. Maybe
> > > > someone else could have add some ideas.
> > > >
> > >
> > > Oh..did not notice this, this time I am including the ML group.
> >
> > Hi,
> >
> > I think that the scenario described above does make sense and that
> > none of the existing schedulers cater to it. Although persistence could be
> > used to achieve much if not all of the desired result. I would be happy
> > to consider a new scheduler that implements source address+port hashing.
> >
> > the persistence mentioned above, how does it work?Can you point to me a
> > link or tutorial on this?

The HOWTO has some information on this
http://www.austintek.com/LVS/LVS-HOWTO/HOWTO/LVS-HOWTO.persistent_connection.html

This ML archive also have various posts by myself and others on the topic.

> Also, do you have any idea if some one already working on this kind of new
> schedule?

I am not aware of anyone else doing similar work.

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

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

<Prev in Thread] Current Thread [Next in Thread>