AIX - best practices?

Hello!

There is a good chance that I'll be trying to deploy PostgreSQL
on some older IBM Power5+ machines (running AIX 5.2 or 5.3).

I wonder if any of you coukl give me some hints on using PostgreSQL
on that platform?

Installation

Looks like I'll be compiling from source (or are there any good packages
available?). It also seems to be a good idea to use xlc instead of gcc
(according to the FAQ).

Tuning

Are there any tuning hints at operating system level that I should pay
more attention to? I.e. jfs/jfs2 mount options, sync settings, etc. etc.?

Anyway, what are your feelings with regard to using PostgreSQL
under AIX? How do you feel it compares to other "big" Unixen as
far as PostgreSQL goes?

Regards,
Dawid

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Re: AIX - best practices?

On Sat, Jun 16, 2007 at 12:00:36PM +0200, Dawid Kuroczko wrote:
> Anyway, what are your feelings with regard to using PostgreSQL
> under AIX?



"Don't".

This is just my personal opinion, and I don't speak for my employer
(especially in this case!), but my feelings are that AIX is an awful,
bletcherous filthy mess that attempts to make UNIX look like a bad
imitation of an AS400.

Just for example, some packages come as RPMs and some as
smit-installable packages, but neither packaging system knows
anything about the other one, so you have the potential for all sorts
of stupid errors that packaging systems were designed to _avoid_,
without any of the flexibility of just compiling it yourself from
source. This foolishness includes packages like, oh, gcc.

Making shared libraries reminds you of the bad old a.out days on
Linux; and it is distressing the IBM hasn't managed to update AIX to
pre-1995 technology.

That's ok, though, because some things (it seems) can't be made into
shared libraries at all. So far as I know, for instance, we were
never able to get PL/R working on AIX, because we just couldn't get
the darn thing to compile. I seem to recall that building Perl in a
way that was adequately flexible ended up taking weeks of
troubleshooting and work on the part of people much smarter than I.
Seneca Cunningham posted either on -general or -hackers (I forget
which, but check the archives) a set of fantastically detailed
contortions necessary to get some set of Postgres things working the
way we wanted. AIX is designed to foil the simplest possible desires
in an effort to solve some problem I haven't learned of yet.

And the above assumes that everything works the way you would expect
-- you know, in the way the manual says it does. I have no idea
what parts of the system are actually tested by IBM's QA department
before new AIX releases ship, but I can say with some certainty that
parts of both libc and fsck -- fsck!! -- got overlooked in the past.
At least when the Linux fanboys push on you the kernel patch of the
millisecond, you know that you can look at the code or ask someone
else about their experiences with it. In the case of IBM, what you
get to ask is, well, IBM Support. Nice people. Excellent phone
manners. Professional and worthy emails suitable for forwarding to
management without even looking for scatalogical remarks. But prompt
and effusive with technical detail? Not so much.

The only slightly saving grace on AIX is a utility called topas,
which does a nice curses-based display of various performance pieces.
It makes most of the tools available on Linux seem primitive; but
then, since most of the tools on Linux _are_ primitive, that
shouldn't be surprising. And it's sort of awful that what you get
for your license fee and inability to look at the code is one nice
tool that works better than some free stuff, but doesn't work
anywhere near as nicely as the RICHPse toolkit that was available
starting with (IIRC) Solaris 2.5. Also, the _usual_ tools that you
might be used to don't exist on AIX, so you have to learn topas, or
fly blind. The large print giveth, and the small print taketh away.

I loathe using AIX. I would run the other way before installing it
on purpose. And given that IBM also supports both Red Hat and SuSE
on POWER5 (and that for at least one non-Postgres workload we tried,
Linux was actually faster on the hardware), I'd use Linux instead.

> How do you feel it compares to other "big" Unixen as far as
> PostgreSQL goes?

As they say in alt.sysadmin.recovery, all operating systems suck.
They don't usually say, however, that AIX, when pronounced as a word, is
the only one that actually describes what it gives you.



All best,
A

--
Andrew Sullivan | ajs@crankycanuck.ca
I remember when computers were frustrating because they *did* exactly what
you told them to. That actually seems sort of quaint now.
--J.D. Baldwin

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