From mboxrd@z Thu Jan 1 00:00:00 1970 From: Werner John MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Message-ID: <15310.40503.356813.663284@rigel.oswf.de> Date: Thu, 18 Oct 2001 11:17:43 +0200 Subject: Re: [linux-lvm] Horrid performance with 2.4.{9,10,12} + LVM + ReiserFS In-Reply-To: <20011018000006.A22777@jensbenecke.de> References: <20011018000006.A22777@jensbenecke.de> Sender: linux-lvm-admin@sistina.com Errors-To: linux-lvm-admin@sistina.com Reply-To: linux-lvm@sistina.com List-Help: List-Post: List-Subscribe: , List-Unsubscribe: , List-Archive: List-Id: Content-Type: text/plain; charset="ibm855" To: linux-lvm@sistina.com Jens Benecke writes: > Hello, Hello, > this is CC'ed to LVM user list and ReiserFS because I don't know who = to > blame currently. ;) >=20 lets, see ... >=20 > I have severe performance problems with a 210G ReiserFS volume sittin= g on a > LVM (1.0.1rc4) spread over three disks (Maxtor 60, 80, 80GB IDE). The= > system is a Duron 650MHz with via686b chipset and UDMA-100 capable ID= E. > /proc/cpuinfo, /proc/ide/via output see below. The hardware seems > performant enough to me. > [...] >=20 > ---------------------------------------------------------------------= ------ > hdparm output for the three disks: >=20 > server: /home# hdparm -tT /dev/hd[abcd] > /dev/hda: > Timing buffer-cache reads: 128 MB in 0.86 seconds =3D148.84 MB/se= c > Timing buffered disk reads: 64 MB in 2.12 seconds =3D 30.19 MB/sec= > /dev/hdc: > Timing buffer-cache reads: 128 MB in 0.84 seconds =3D152.38 MB/se= c > Timing buffered disk reads: 64 MB in 2.28 seconds =3D 28.07 MB/sec= > /dev/hdd: > Timing buffer-cache reads: 128 MB in 0.86 seconds =3D148.84 MB/se= c > Timing buffered disk reads: 64 MB in 2.36 seconds =3D 27.12 MB/sec= Well, you have 1 disk on a single channel (hda) and the other two as ma= ster and slave on *one* channel. That's the bottleneck. If the disks are accessed individually, you get the full performance (more or less). But= if *both* disks have to respond, performance drops horribly. Best is to get a third IDE controller. Yours, =09Werner >=20 >=20 > bonnie++ output for the LVM volume: ---------------------------------= ------ > Version 1.01d ------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 > server 256M 5596 97 24539 34 6926 7 5194 87 24662 17= 115.1 1 > ------Sequential Create------ --------Random Crea= te-------- > -Create-- --Read--- -Delete-- -Create-- --Read---= -Delete-- > files /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP= /sec %CP > 16 7965 99 +++++ +++ 10546 99 5458 92 +++++ +++= 8214 90 > server,256M,5596,97,24539,34,6926,7,5194,87,24662,17,115.1,1,16,7965,= 99,+++++,++ > ---------------------------------------------------------------------= ------ >=20 >=20 >=20 >=20 > --=20 > Jens Benecke =B7=B7=B7=B7=B7=B7=B7=B7 http://www.hitchhikers.de/ - Eu= ropas Mitfahrzentrale >=20 > Crypto regulations will only hinder criminals who obey the law. >=20 > =5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F= =5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F= > linux-lvm mailing list > linux-lvm@sistina.com > http://lists.sistina.com/mailman/listinfo/linux-lvm > read the LVM HOW-TO at http://www.sistina.com/lvm/Pages/howto.html