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
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========================================================================
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,+++++,+++,+++++,+++,
+++++,+++,+++++,+++,+++++,+++,+++++,+++
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========================================================================
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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