I use Postgresql on Linux but am no expert even there. I've been
asked to help setup Postgresql on a MS Windows cluster for
high-availability, which is way out of my skillset.

I've read the 8.2.5 documentation on
http://www.postgresql.org/docs/8.2/s...ilability.html
and
http://pgfoundry.org/softwaremap/tro...p?form_cat=392
and
this newsgroup's recent postings.

Looks like the topic is leading-edge enough to need expert advice.
Free advice via postings or emails or phone calls would be good.
There might be budget for paid consulting (I don't have any control
over that, and no one has hinted funding is available, but it is
possible).

BTW: This is for a large corporation which is beginning to take OSS
seriously. The project's success/failure will probably impact Postgresql's
opportunities generally.

You can post responses, or email to my home addr (below).

--
Harry George
hgg9140 (AT) seanet (DOT) com www.seanet.com/~hgg9140

Harry George schrieb:
Well high-availability can be a lot.

I think you will get better responses if you ask specific questions.

OSS does not mean you wil find experts that provide you with a complete
solution for free.


If you have a job to offer, then you should choose the right topic.

If this project of yours is a nice OSS project which will be interesting
to a wide range of people then you should mention this, otherwise folks
may think that someone is looking for free slaves that do all the work
in the name of OSS.

Cheers Stefan

Harry George <hgg9140 (AT) seanet (DOT) com> wrote:
You should first get a clear picture what you (or the people that pay you)
really mean by "high availability".

Don't let yourself be fooled by thinking that "7x24, zero downtime" is
a good specification.

The buzzword here is "service level agreement". You need to sort out
against what kinds of involuntary service interruption you want to
protect the database. Hardware failure? Software failure? Data corruption?
Power outage? DBA typos? Hurricanes flooding the server room?
They all might need different strategies.
What is the acceptable downtime in any of these cases?
And how long and how frequently can there be a scheduled downtime for
software upgrades?

Usually the demands for "7x24, zero downtime" become less vehement if
you estimate the costs for a second server room at least 500 miles away
with fast network connection or the price of an industry scale tape library
or the salary of additional employees who will get up at 3 a.m. when an
alert comes in.

And - frankly - since your customer even considers using a Windows
computer for a high availibility setup makes me think that either
they do not know what they are talking about or they do not really
need and want a very high level of high availibility.

Your estimate is correct: you always need to invest brains and money if
you want to end up with a high availibility setup that will do
any good.

Meet hardware problems with redundancy.
Meet software problems and DBA/User errors with a good backup strategy.
Consider hot standby to minimize downtime.
Hire a DBA who knows PostgreSQL and the operating system well.

Contact your friendly neighbourhood PostgreSQL support company.

The PostgreSQL community bows in awe :^)

If they are beginning now, they are a bit late. But better late than never.
With companies who have no experience with open source software there is
always a certain learning curve to expect. Common pitfalls are:

- Using OSS means we have no expenses (true is: you still need to invest
in hardware, brain power and support).
- Using OSS means that we are at the mercy of a handful of potheads with
whom we have no contract, so there is no guarantee that anybody will
solve our problems and bugs (true is: there are many companies who
sell good support for OSS. And even if you have a support contract with
Oracle that does not mean that you can be sure that all your bugs will
be found and fixed).

That all said, I want to chime in with the other reply that you are welcome
to come here (or to the PostgreSQL mailing lists) with your specific
problems and questions, and if your questions are understandable you will
very likely get meaningful replies.

Yours,
Laurenz Albe

Stefan Braumeister <sbraumi (AT) gmx (DOT) net> writes:


Hmmm. I wasn't looking for answers yet. I was looking for technical
contacts.

Here is the context. I'm the OSS product manager for a large
aerospace firm which is mostly very COTS-oriented. I maintain a depot
of 500 packages including the GNU toolchain, languages, graphics,
math, web, databases, GIS, flightsim, AI, etc. I build them on a
variety of UNIX, Linux, and MS Windows systems, from laptops to
16-core servers and mainframes. I support people worldwide with
selection, install, config, and use.

This effort (since the mid 1990s) has been at times, uh,
career-limiting. Especially so in multi-year negotiations with the
DBA organization, which is almost entirely focused on a few COTS DBMS.

So when a user asked for help, I recognized a "put up or shut up"
situation. Normally, I can solve Postgrsql issues by RTFM and
prototyping. I always start with a literature search. In this case
the user just said "high availability on a MS WIndows cluster". I've
already responded to him with early findings and more questions as you
suggest.

I also realized I needed some direct discussion with folks who
understood the tradeoffs. So I was looking for contacts, not specific
answers to specific questions.

--
Harry George
hgg9140 (AT) seanet (DOT) com www.seanet.com/~hgg9140

Harry George <hgg9140 (AT) seanet (DOT) com> wrote:
That is good.

To me, and probably to you too, it sounds odd if somebody says "I want
to achieve goal X, and I want it achieved with software Y."
How does he or she know that software Y is a good solution?
Particularly if X is a bit vague.

I want to recommend the mailing lists, see
http://www.postgresql.org/community/lists/

The pgsql-general list is read by basically everyone who is into
PostgreSQL and might be able and willing to help.

Maybe pgsql-admin is also a good mailing list for the kind of questions
that you might have.

Yours,
Laurenz Albe

There is a large airospace company a couple of blocks away from my
place, they work a lot with OSS, I know one of their kernel developers:-)

Pretty much the same in our company. Production basically uses Oracle.
We at research do most of our development on postgresql.

Getting the requirements is always an important but often neglegted task.

Not sure if you find anyone from your area on this list, but you can
always ask your questions here.

Laurenz Albe <invite (AT) spam (DOT) to.invalid> writes:

Thanks for the leads.

BTW: He may know his needs but hasn't conveyed them to me. Also, you
can appreciate that sometimes OS choices are made by executives far
removed from technical facts-and-data. I have faith that reality will
win in the end.

--
Harry George
hgg9140 (AT) seanet (DOT) com www.seanet.com/~hgg9140