Jens Benecke writes: > Hello, Hello, > this is CC'ed to LVM user list and ReiserFS because I don't know who to > blame currently. ;) > lets, see ... > > I have severe performance problems with a 210G ReiserFS volume sitting 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 IDE. > /proc/cpuinfo, /proc/ide/via output see below. The hardware seems > performant enough to me. > [...] > > --------------------------------------------------------------------------- > hdparm output for the three disks: > > server: /home# hdparm -tT /dev/hd[abcd] > /dev/hda: > Timing buffer-cache reads: 128 MB in 0.86 seconds =148.84 MB/sec > Timing buffered disk reads: 64 MB in 2.12 seconds = 30.19 MB/sec > /dev/hdc: > Timing buffer-cache reads: 128 MB in 0.84 seconds =152.38 MB/sec > Timing buffered disk reads: 64 MB in 2.28 seconds = 28.07 MB/sec > /dev/hdd: > Timing buffer-cache reads: 128 MB in 0.86 seconds =148.84 MB/sec > Timing buffered disk reads: 64 MB in 2.36 seconds = 27.12 MB/sec Well, you have 1 disk on a single channel (hda) and the other two as master 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, Werner > > > 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 Create-------- > -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,+++++,++ > --------------------------------------------------------------------------- > > > > > -- > Jens Benecke ········ http://www.hitchhikers.de/ - Europas Mitfahrzentrale > > Crypto regulations will only hinder criminals who obey the law. > > _______________________________________________ > 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
