From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ming Zhang Subject: RE: raid0 low performance Date: Fri, 01 Jul 2005 09:17:13 -0400 Message-ID: <1120223833.5507.40.camel@localhost.localdomain> References: <200507011255.j61CtXp10224@www.watkins-home.com> Reply-To: mingz@ele.uri.edu Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="=-evx3O705t28/xszu4jSU" Return-path: In-Reply-To: <200507011255.j61CtXp10224@www.watkins-home.com> Sender: linux-raid-owner@vger.kernel.org To: Guy Cc: 'Linux RAID' List-Id: linux-raid.ids --=-evx3O705t28/xszu4jSU Content-Type: text/plain Content-Transfer-Encoding: quoted-printable On Fri, 2005-07-01 at 08:55 -0400, Guy wrote: > I think you should test 2 or more disks at the same time. This would pro= ve > that your system can or can't move more than about 60MB/s. i tested and seems that 90MB/s is the max here. if i run 2 program copy on 2 disks independently on same card, both of them bound at 45MB/s if i run 3 program copy on 3 disks independently on same card, both of them bound at 27 or 28MB/s so total is still 90MB/s if i run 2 program copy on 2 disks but one is on 4 port marvel and another is 8 port marvel, then both of the bound at 55MB/s which is disk limitation. so i guess the card or bus has problem. i will check bus speed soon. >=20 > My old P3-500 SMP can move at least 150MB/s. But I have 3 SCSI buses and= 3 > PCI buses. >=20 > Guy >=20 ming > > -----Original Message----- > > From: linux-raid-owner@vger.kernel.org [mailto:linux-raid- > > owner@vger.kernel.org] On Behalf Of Ming Zhang > > Sent: Thursday, June 30, 2005 10:16 PM > > To: Linux RAID > > Subject: raid0 low performance > >=20 > > I meet some strange low performance when run RAID0 with vanilla kernel > > 2.4.27/2.6.11.12. > >=20 > > My box is a 2.8G P4 and 1G RAM. 8 400GB SATA disk and A marvel 8port > > controller. I run marvel 3.4.1 driver. I wrote a small program to write > > device sequentially and SYNCHRONOUSLY. > >=20 > > This is performance of 1 disk. looks fine. > >=20 > > 1048576Bytes * 1024 : 55.466MB/s > > 524288Bytes * 2048 : 55.830MB/s > > 262144Bytes * 4096 : 55.782MB/s > > 131072Bytes * 8192 : 55.567MB/s > > 65536Bytes * 16384 : 55.926MB/s > > 32768Bytes * 32768 : 54.344MB/s > > 16384Bytes * 65536 : 41.415MB/s > > 8192Bytes * 65536 : 26.499MB/s > > 4096Bytes * 65536 : 15.110MB/s > > 2048Bytes * 65536 : 8.422MB/s > > 1024Bytes * 65536 : 4.318MB/s > >=20 > > But when run 2 disk raid0, there is only 10% improvement. > >=20 > > md3 : active raid0 sdb[1] sda[0] > > 781422592 blocks 64k chunks > > 1048576Bytes * 1024 : 67.300MB/s > > 524288Bytes * 2048 : 66.796MB/s > > 262144Bytes * 4096 : 65.728MB/s > > 131072Bytes * 8192 : 65.017MB/s > > 65536Bytes * 16384 : 59.223MB/s > > 32768Bytes * 32768 : 49.766MB/s > > 16384Bytes * 65536 : 39.162MB/s > > 8192Bytes * 65536 : 26.386MB/s > > 4096Bytes * 65536 : 15.084MB/s > > 2048Bytes * 65536 : 8.383MB/s > > 1024Bytes * 65536 : 4.303MB/s > >=20 > > And when use 4 disks, the speed is slower! > > md0 : active raid0 sdh[3] sdg[2] sdf[1] sde[0] > > 1562845184 blocks 64k chunks > > 1048576Bytes * 1024 : 58.032MB/s > > 524288Bytes * 2048 : 56.994MB/s > > 262144Bytes * 4096 : 58.289MB/s > > 131072Bytes * 8192 : 65.999MB/s > > 65536Bytes * 16384 : 59.723MB/s > > 32768Bytes * 32768 : 50.061MB/s > > 16384Bytes * 65536 : 38.689MB/s > > 8192Bytes * 65536 : 26.169MB/s > > 4096Bytes * 65536 : 15.169MB/s > > 2048Bytes * 65536 : 8.378MB/s > > 1024Bytes * 65536 : 4.287MB/s > >=20 > >=20 > > Any hint on this? > >=20 > > * I do not know how to check current PCI bus speed and I am not sure > > whether is limited by that. It is a 64bit card but I am not sure if it > > is run at 66MHZ. Should be, but want to check to make sure. > > * I tested each disk and all disk performs OK. > >=20 > >=20 > > Thanks > >=20 > >=20 > > Ming >=20 >=20 --=-evx3O705t28/xszu4jSU Content-Type: application/pgp-signature; name=signature.asc Content-Description: This is a digitally signed message part -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.6 (GNU/Linux) iD8DBQBCxUJZSYbkL5BnVYoRAjaiAJ9VVrmjfMzpD5/XL3Pu5PTt6mzj9ACfdPAB Begy/r1v3n7G0mwbujkwfpw= =c9lL -----END PGP SIGNATURE----- --=-evx3O705t28/xszu4jSU--