Re: questions about disk configurations

I don't know whether you have read this link but it was helpful to me.

http://www.ca.postgresql.org/docs/momjian/hw_performance/0.html

It discusses PostgreSQL Hardware Performance Tuning.

Hope it helps!

Keith Bottner

-----Original Message-----
From: pgsql-performance-owner@postgresql.org
[mailto:pgsql-performance-owner@postgresql.org] On Behalf Of Hubert
depesz Lubaczewski
Sent: Monday, December 09, 2002 7:05 AM
To: Adrian 'Dagurashibanipal' von Bidder;
pgsql-performance@postgresql.org
Subject: Re: [PERFORM] questions about disk configurations


On Mon, Dec 09, 2002 at 01:01:58PM +0100, Adrian 'Dagurashibanipal' von
Bidder wrote:
> A bit more data is needed before anybody can give you more help:
>  - what is your budget?
>  - how big will your databases be?
>  - what's the read/write ratio?

my question as for now is purely theoretical. i'm not asking about any
specific situation, but me may talk about medium sized web size. budget
is irrelevant (i'd like to talk *only* about harddrives, not memory,
architescure and so on).

>  - as you correctly said: distribute the load on many spindles. On a
> busy database, 4*20G is probably faster than 1*80G

as i said: i know that 3 disks are bettar than 1 (as for postgres
installation, because system data and swap should be on 4th disc - but
this is obvious).

> beyound this, experiences vary. RAID1 and RAID5 are rated differently
> by different people - and especially with RAID5 there are (I think)
> really performance differencies between the various products. RAID0 is

> fastest, of course, but you probably care for your data.

that's exactly what i'm asking about: which raid is best suited for
which data amongst out 3 sets (xlog, tables, indices). or maybe for some
types of data single disc is better than raid for some strange reason?
is it better to (when having 2 discs) setup raid 0/1 or to use tham
separatelly as xlog/tables?

depesz

--
hubert depesz lubaczewski                          http://www.depesz.pl/
------------------------------------------------------------------------
Mój Boże, spraw abym milczał, dopóki się nie upewnię,  że  naprawdę  mam
coś do powiedzenia.                                      (c) 1998 depesz


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