pg.ddx.io pgsql-performance@postgresql.org mailing list archive help / color / mirror / Atom feed From: Enrico Sirola <enrico.sirola@gmail.com>
To: Craig Ringer <craig@postnewspapers.com.au>
Cc: Matthew <matthew@flymine.org>
Cc: pgsql-performance@postgresql.org
Subject: Re: Performance increase with elevator=deadline
Date: Fri, 18 Apr 2008 16:38:05 +0200
Message-ID: <544D07A2-EB3F-4D91-A749-0C4D5D38AB80@gmail.com> (raw )
In-Reply-To: <47FFA7FF.10801@postnewspapers.com.au >
References: <D960CB61B694CF459DCFB4B0128514C201FA62C8@exadv11.host.magwien.gv.at >
<C050E63A-2209-4E89-AA99-6A327CCE7380@torgo.978.org >
<Pine.LNX.4.64.0804111736580.20402@aragorn.flymine.org >
<47FFA7FF.10801@postnewspapers.com.au >
Hi,
Il giorno 11/apr/08, alle ore 20:03, Craig Ringer ha scritto:
>
> Speaking of I/O performance with PostgreSQL, has anybody here done
> any testing to compare results with LVM to results with the same
> filesystem on a conventionally partitioned or raw volume? I'd
> probably use LVM even at a performance cost because of its admin
> benefits, but I'd be curious if there is any known cost for use with
> Pg. I've never been able to measure one with other workloads.
I performed some tests some time ago. LVM is significantly slower.
The disk subsystem is a HP P400/512MB battery-backed controller with 4
disks in raid 10.
See the tests:
ext3 tests:
bonnie++ -s 16000 -u 0 -f -b
=
=
=
=
=
=
=
========================================================================
Version 1.03 ------Sequential Output------ --Sequential Input-
--Random-
-Per Chr- --Block-- -Rewrite- -Per Chr- --Block--
--Seeks--
Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec
%CP /sec %CP
16000M 153637 50 78895 17 204124
17 700.6 1
------Sequential Create------ --------Random
Create--------
-Create-- --Read--- -Delete-- -Create-- --Read---
-Delete--
files /sec %CP /sec %CP /sec %CP /sec %CP /sec
%CP /sec %CP
16 2233 10 +++++ +++ 2606 8 2255 10 +++++ ++
+ 2584 7
16000M,,,153637,50,78895,17,,,204124,17,700.6,1,16,2233,10,+++++,+++,
2606,8,2255,10,+++++,+++,2584,7
bonnie++ -s 16000 -u 0 -f
=
=
=
=
=
=
=
========================================================================
Version 1.03 ------Sequential Output------ --Sequential Input-
--Random-
-Per Chr- --Block-- -Rewrite- -Per Chr- --Block--
--Seeks--
Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec
%CP /sec %CP
16000M 162223 51 77277 17 207055
17 765.3 1
------Sequential Create------ --------Random
Create--------
-Create-- --Read--- -Delete-- -Create-- --Read---
-Delete--
files /sec %CP /sec %CP /sec %CP /sec %CP /sec
%CP /sec %CP
16 +++++ +++ +++++ +++ +++++ +++ +++++ +++ +++++ +++
+++++ +++
16000M,,,162223,51,77277,17,,,207055,17,765.3,1,16,+++++,+++,+++++,+++,
+++++,+++,+++++,+++,+++++,+++,+++++,+++
=
=
=
=
=
=
=
========================================================================
LVM tests:
bonnie++ -u 0 -f -s 16000 -b
Version 1.03 ------Sequential Output------ --Sequential Input-
--Random-
-Per Chr- --Block-- -Rewrite- -Per Chr- --Block--
--Seeks--
Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec
%CP /sec %CP
16000M 153768 52 53420 13 177414
15 699.8 1
------Sequential Create------ --------Random
Create--------
-Create-- --Read--- -Delete-- -Create-- --Read---
-Delete--
files /sec %CP /sec %CP /sec %CP /sec %CP /sec
%CP /sec %CP
16 2158 9 +++++ +++ 2490 7 2177 9 +++++ ++
+ 2460 7
16000M,,,153768,52,53420,13,,,177414,15,699.8,1,16,2158,9,+++++,+++,
2490,7,2177,9,+++++,+++,2460,7
bonnie++ -u 0 -f -s 16000
Version 1.03 ------Sequential Output------ --Sequential Input-
--Random-
-Per Chr- --Block-- -Rewrite- -Per Chr- --Block--
--Seeks--
Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec
%CP /sec %CP
16000M 161476 53 54904 13 171693
14 774.3 1
------Sequential Create------ --------Random
Create--------
-Create-- --Read--- -Delete-- -Create-- --Read---
-Delete--
files /sec %CP /sec %CP /sec %CP /sec %CP /sec
%CP /sec %CP
16 +++++ +++ +++++ +++ +++++ +++ +++++ +++ +++++ +++
+++++ +++
16000M,,,161476,53,54904,13,,,171693,14,774.3,1,16,+++++,+++,+++++,+++,
+++++,+++,+++++,+++,+++++,+++,+++++,+++
Bye,
e.
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To: pgsql-performance@postgresql.org
Cc: enrico.sirola@gmail.com, craig@postnewspapers.com.au, matthew@flymine.org
Subject: Re: Performance increase with elevator=deadline
In-Reply-To: <544D07A2-EB3F-4D91-A749-0C4D5D38AB80@gmail.com>
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