Re: [PATCH] Sloppy TCP, SH rebalancing, SHP scheduling

To: Alexander Frolkin <avf@xxxxxxxxxxxxxx>
Subject: Re: [PATCH] Sloppy TCP, SH rebalancing, SHP scheduling
Cc: lvs-devel@xxxxxxxxxxxxxxx
From: Julian Anastasov <ja@xxxxxx>
Date: Mon, 10 Jun 2013 22:31:16 +0300 (EEST)

On Fri, 7 Jun 2013, Alexander Frolkin wrote:

> Hi,
> >     OTOH, the difference is very small: the port.
> > The problem is that we add only global controls, it
> > would be good if we can configure such parameters
> > per virtual service:
> > - use port in source hash
> Well, this one can be configured per service by changing the scheduler.
> Or are you concerned about the fact that the code for SHP and SH is
> essentially the same and should be merged?

        Yes, if we find a way to configure SH, there is
no need for separate SHP.

> >     The problem here is that we call ip_vs_service_find()
> > after checking th->syn. So, may be it is better to have
> > global sysctl flag here, as in your patch.
> I don't think a global sysctl is a problem for sloppy TCP (SCTP).  I
> think it's unlikely that you'll want to enable it on one service but not
> on another.


> > IP_VS_SVC_F_SCHED1: scheduler flag 1 (SH: fallback to other dest if 
> > weight=0), i.e. the sh_rebalance flag
> > IP_VS_SVC_F_SCHED2: scheduler flag 1 (SH: add port in hash)
> > IP_VS_SVC_F_SCHED3: scheduler flag 2 (SH: consider mask/plen)
> This isn't a bad idea, and it will probably find other uses, too.
> Is there a reason why the SH fallback behaviour shouldn't be default?
> That is, is there a reason why the current behaviour (client connection
> gets reset if it is directed to a realserver with weight 0) is
> desirable?

        I don't know, the authors preferred this behaviour.

> >     Note that latest SH version supports weights and
> > RCU, you have to consider it for next patch versions.
> I'll take a look at the latest version.


Julian Anastasov <ja@xxxxxx>
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