From:
Simon Riggs <simon(at)2ndQuadrant(dot)com>
To:
Robert Haas <robertmhaas(at)gmail(dot)com>,
Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com>
Cc:
Hannu Krosing <hannu(at)2ndquadrant(dot)com>, greg(at)2ndquadrant(dot)com,
Josh Berkus <josh(at)postgresql(dot)org>,
Stefan Kaltenbrunner <stefan(at)kaltenbrunner(dot)cc>,
pgsql-hackers(at)postgresql(dot)org
Subject:
Re: Sync Rep Design
Date:
2011-01-02 13:41:13
Message-ID:
1293975673.2090.464.camel@ebony (view raw or flat )
Thread:
2010-12-30 17:26:12 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2010-12-30 17:42:22 from Stefan Kaltenbrunner <stefan(at)kaltenbrunner(dot)cc>
2010-12-30 19:04:13 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2010-12-30 20:07:16 from Robert Treat <rob(at)xzilla(dot)net>
2010-12-30 20:24:09 from Aidan Van Dyk <aidan(at)highrise(dot)ca>
2010-12-31 03:26:51 from Joshua Tolley <eggyknap(at)gmail(dot)com>
2010-12-31 11:51:55 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2010-12-30 20:36:30 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2010-12-30 20:51:19 from Robert Treat <rob(at)xzilla(dot)net>
2010-12-30 21:01:18 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2010-12-30 21:08:50 from Stefan Kaltenbrunner <stefan(at)kaltenbrunner(dot)cc>
2010-12-30 21:27:11 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2010-12-31 08:15:41 from Stefan Kaltenbrunner <stefan(at)kaltenbrunner(dot)cc>
2010-12-30 20:39:05 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2010-12-30 20:55:28 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2010-12-30 20:11:40 from Marti Raudsepp <marti(at)juffo(dot)org>
2010-12-30 21:10:00 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2010-12-30 20:42:23 from Stefan Kaltenbrunner <stefan(at)kaltenbrunner(dot)cc>
2010-12-30 21:23:55 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2010-12-31 08:27:29 from Stefan Kaltenbrunner <stefan(at)kaltenbrunner(dot)cc>
2010-12-31 10:26:11 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2010-12-31 12:33:19 from Aidan Van Dyk <aidan(at)highrise(dot)ca>
2010-12-31 16:56:38 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2011-01-01 13:13:07 from Jeff Janes <jeff(dot)janes(at)gmail(dot)com>
2011-01-01 14:03:35 from Stefan Kaltenbrunner <stefan(at)kaltenbrunner(dot)cc>
2011-01-01 14:15:45 from Robert Haas <robertmhaas(at)gmail(dot)com>
2011-01-01 15:12:19 from Stefan Kaltenbrunner <stefan(at)kaltenbrunner(dot)cc>
2011-01-01 16:55:57 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2011-01-01 17:13:24 from Stefan Kaltenbrunner <stefan(at)kaltenbrunner(dot)cc>
2011-01-01 17:29:20 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2011-01-01 17:49:44 from Stefan Kaltenbrunner <stefan(at)kaltenbrunner(dot)cc>
2011-01-01 19:03:30 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2011-01-01 16:35:59 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2011-01-02 20:27:10 from Jeff Janes <jeff(dot)janes(at)gmail(dot)com>
2010-12-30 21:47:42 from Robert Haas <robertmhaas(at)gmail(dot)com>
2010-12-31 01:15:10 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2010-12-31 01:57:34 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2010-12-31 05:02:13 from Robert Haas <robertmhaas(at)gmail(dot)com>
2010-12-31 07:50:43 from Hannu Krosing <hannu(at)2ndquadrant(dot)com>
2011-01-02 20:13:46 from MARK CALLAGHAN <mdcallag(at)gmail(dot)com>
2011-01-02 20:53:23 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2011-01-03 11:10:40 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2010-12-30 21:27:03 from Robert Haas <robertmhaas(at)gmail(dot)com>
2010-12-31 00:47:37 from Jim Nasby <jim(at)nasby(dot)net>
2010-12-31 01:38:32 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2010-12-31 01:07:53 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2010-12-31 07:50:07 from Hannu Krosing <hannu(at)2ndquadrant(dot)com>
2010-12-31 10:06:12 from Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com>
2010-12-31 10:39:32 from Stefan Kaltenbrunner <stefan(at)kaltenbrunner(dot)cc>
2010-12-31 10:42:15 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2010-12-31 11:48:57 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2010-12-31 12:40:15 from Robert Haas <robertmhaas(at)gmail(dot)com>
2010-12-31 12:57:30 from Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com>
2010-12-31 13:39:19 from Robert Haas <robertmhaas(at)gmail(dot)com>
2010-12-31 13:48:41 from Stefan Kaltenbrunner <stefan(at)kaltenbrunner(dot)cc>
2010-12-31 14:13:50 from Robert Haas <robertmhaas(at)gmail(dot)com>
2011-01-01 00:20:54 from Josh Berkus <josh(at)postgresql(dot)org>
2010-12-31 12:40:58 from Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com>
2010-12-31 19:15:59 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2011-01-01 13:59:06 from Stefan Kaltenbrunner <stefan(at)kaltenbrunner(dot)cc>
2011-01-01 16:28:42 from Dimitri Fontaine <dimitri(at)2ndQuadrant(dot)fr>
2011-01-01 16:37:12 from Stefan Kaltenbrunner <stefan(at)kaltenbrunner(dot)cc>
2011-01-01 17:03:48 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2011-01-01 19:29:45 from Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com>
2011-01-01 17:30:29 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2011-01-01 22:40:21 from Josh Berkus <josh(at)postgresql(dot)org>
2011-01-01 23:08:42 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2011-01-02 03:11:10 from Aidan Van Dyk <aidan(at)highrise(dot)ca>
2011-01-02 10:39:45 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2011-01-02 08:35:07 from Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com>
2011-01-02 09:20:39 from Stefan Kaltenbrunner <stefan(at)kaltenbrunner(dot)cc>
2011-01-02 09:20:40 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2011-01-02 10:39:51 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2011-01-02 12:47:17 from Dimitri Fontaine <dimitri(at)2ndQuadrant(dot)fr>
2011-01-02 16:44:01 from Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com>
2011-01-02 17:53:51 from Dimitri Fontaine <dimitri(at)2ndQuadrant(dot)fr>
2011-01-02 20:58:35 from Magnus Hagander <magnus(at)hagander(dot)net>
2011-01-02 21:24:27 from Dimitri Fontaine <dimitri(at)2ndQuadrant(dot)fr>
2011-01-04 18:40:25 from Josh Berkus <josh(at)postgresql(dot)org>
2011-01-04 22:00:53 from Dimitri Fontaine <dimitri(at)2ndQuadrant(dot)fr>
2011-01-04 22:18:13 from Josh Berkus <josh(at)postgresql(dot)org>
2011-01-04 22:24:43 from Dimitri Fontaine <dimitri(at)2ndQuadrant(dot)fr>
2011-01-04 23:20:21 from Josh Berkus <josh(at)agliodbs(dot)com>
2010-12-31 21:18:15 from Hannu Krosing <hannu(at)2ndquadrant(dot)com>
2011-01-01 11:54:35 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2011-01-02 04:36:10 from Robert Haas <robertmhaas(at)gmail(dot)com>
2011-01-02 10:59:32 from Hannu Krosing <hannu(at)2ndquadrant(dot)com>
2011-01-02 13:41:13 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2011-01-02 16:54:29 from Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com>
2011-01-02 21:19:46 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2011-01-04 18:28:30 from Josh Berkus <josh(at)agliodbs(dot)com>
2011-01-04 18:51:45 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
2011-01-04 19:04:21 from "Joshua D(dot) Drake" <jd(at)commandprompt(dot)com>
2011-01-04 19:50:17 from Stefan Kaltenbrunner <stefan(at)kaltenbrunner(dot)cc>
2011-01-04 19:54:04 from Robert Haas <robertmhaas(at)gmail(dot)com>
2011-01-05 01:59:57 from Greg Smith <greg(at)2ndquadrant(dot)com>
2011-01-04 19:04:37 from Robert Haas <robertmhaas(at)gmail(dot)com>
2011-01-03 01:30:12 from Hannu Krosing <hannu(at)2ndquadrant(dot)com>
2011-01-01 19:41:55 from Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com>
2011-01-01 22:41:10 from Simon Riggs <simon(at)2ndQuadrant(dot)com>
Lists:
pgsql-hackers
On Sat, 2011-01-01 at 23:36 -0500, Robert Haas wrote:
> On Sat, Jan 1, 2011 at 6:54 AM, Simon Riggs <simon(at)2ndquadrant(dot)com> wrote:
> > Yes, working out the math is a good idea. Things are much clearer if we
> > do that.
> >
> > Let's assume we have 98% availability on any single server.
> >
> > 1. Having one primary and 2 standbys, either of which can acknowledge,
> > and we never lock up if both standbys fail, then we will have 99.9992%
> > server availability. (So PostgreSQL hits "5 Nines", with data
> > guarantees). ("Maximised availability")
>
> I don't agree with this math. ...(snip by Simon)... 99.96%.
OK, so that is at least 99.96%. Cool.
The key point here is not (1), but option (4).
The approach advocated by Heikki and yourself gives us 94% availability.
IMHO that is ridiculous, and I will not accept that as the *only* way
forwards, for that reason, whoever advocates it or for how long they
keep arguing. I do accept that some wish that as an option.
If we are to have a sensible technical debate with an eventual end, you
must answer the points placed in front of you, not just sidestep and try
to point out problems somewhere else. All analysis must be applied to
all options, not just those options advocated by someone else. I've been
asking for a failure mode analysis for months and it never comes in
full.
I'm more than happy to discuss your additional points once we are clear
on the 94% because it is pivotal to everything I've been proposing.
--
Simon Riggs http://www.2ndQuadrant.com/books/
PostgreSQL Development, 24x7 Support, Training and Services
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