From mboxrd@z Thu Jan 1 00:00:00 1970 From: dwu Subject: An multipath performance issue on RHEL 5 Date: Tue, 13 Jan 2009 17:11:23 +0800 Message-ID: <496C5ABB.8040602@redhat.com> Reply-To: device-mapper development Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: quoted-printable Return-path: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com To: dm-devel@redhat.com List-Id: dm-devel.ids A customer has done a test of multipath on RHEL 5, and he found that the=20 speed is 30-40MB/sec, but it can reach 160MB/sec when using EMC=20 powerpath or using multipath on RHEL 4. That customer just uses the=20 default configuration and I found there was a little difference between=20 the configurationfor EMC DGC in the hwtable of multipath on RHEL4 and=20 RHEL5. But I don't think that will impact performance. I have no idea=20 now. Who can help me? thanks. r +=3D store_hwe_ext(hw, "DGC", "*", GROUP_BY_PRIO, DEFAULT_GETUID, "/sbin/mpath_prio_emc /dev/%n", "1 emc", "1 queue_if_no_path", "emc_clariion", -FAILBACK_IMMEDIATE, "LUNZ", 0, //no_path_retry, 0, //rr_weight, 0); //rr_min_io { .vendor =3D "DGC", .product =3D ".*", .bl_product =3D "LUNZ", .getuid =3D DEFAULT_GETUID, .getprio =3D "/sbin/mpath_prio_emc /dev/%n", .features =3D "1 queue_if_no_path", .hwhandler =3D "1 emc", .selector =3D DEFAULT_SELECTOR, .pgpolicy =3D GROUP_BY_PRIO, .pgfailback =3D -FAILBACK_IMMEDIATE, .rr_weight =3D RR_WEIGHT_NONE, .no_path_retry =3D (300 / DEFAULT_CHECKINT), .minio =3D DEFAULT_MINIO, .checker_name =3D EMC_CLARIION, }, [root@clnode2 ~]# hdparm -t /dev/mapper/mpath0 /dev/mapper/mpath0: Timing buffered disk reads: 118 MB in 3.01 seconds =3D 39.22 MB/sec [root@clnode2 ~]# hdparm -t /dev/mapper/mpath5 /dev/mapper/mpath5: Timing buffered disk reads: 132 MB in 3.04 seconds =3D 43.38 MB/sec [root@clnode2 tmp]# hdparm -t /dev/sdm /dev/sdm: Timing buffered disk reads: 112 MB in 3.04 seconds =3D 36.89 MB/sec [root@clnode2 tmp]# hdparm -t /dev/sdaa /dev/sdaa: Timing buffered disk reads: 108 MB in 3.02 seconds =3D 35.81 MB/sec [root@clnode2 tmp]# hdparm -t /dev/sdf /dev/sdf: Timing buffered disk reads: read() failed: Input/output error [root@clnode2 tmp]# hdparm -t /dev/sdt /dev/sdt: Timing buffered disk reads: read() failed: Input/output error [root@clnode2 tmp]# multipath -l mpath2 (36006016067a21a001c72ef78bdd0dd11) dm-9 DGC,RAID 10 [size=3D43G][features=3D1 queue_if_no_path][hwhandler=3D1 emc] \_ round-robin 0 [prio=3D0][active] \_ 1:0:0:1 sdp 8:240 [active][undef] \_ 2:0:0:1 sdb 8:16 [active][undef] \_ round-robin 0 [prio=3D0][enabled] \_ 2:0:1:1 sdi 8:128 [active][undef] \_ 1:0:1:1 sdw 65:96 [active][undef] mpath1 (36006016067a21a00901b9565bdd0dd11) dm-10 DGC,RAID 10 [size=3D3.5G][features=3D1 queue_if_no_path][hwhandler=3D1 emc] \_ round-robin 0 [prio=3D0][active] \_ 2:0:0:3 sdd 8:48 [active][undef] \_ 1:0:0:3 sdr 65:16 [active][undef] \_ round-robin 0 [prio=3D0][enabled] \_ 2:0:1:3 sdk 8:160 [active][undef] \_ 1:0:1:3 sdy 65:128 [active][undef] mpath0 (36006016067a21a00029dbb1dbed0dd11) dm-0 DGC,RAID 10 [size=3D30G][features=3D1 queue_if_no_path][hwhandler=3D0] \_ round-robin 0 [prio=3D0][active] \_ 2:0:1:0 sdh 8:112 [active][undef] \_ round-robin 0 [prio=3D0][enabled] \_ 2:0:0:0 sda 8:0 [active][undef] \_ round-robin 0 [prio=3D0][enabled] \_ 1:0:0:0 sdo 8:224 [active][undef] \_ round-robin 0 [prio=3D0][enabled] \_ 1:0:1:0 sdv 65:80 [active][undef] mpath6 (36006016067a21a007c189b0cbed0dd11) dm-8 DGC,RAID 10 [size=3D1.0G][features=3D1 queue_if_no_path][hwhandler=3D1 emc] \_ round-robin 0 [prio=3D0][active] \_ 2:0:1:6 sdn 8:208 [active][undef] \_ 1:0:1:6 sdab 65:176 [active][undef] \_ round-robin 0 [prio=3D0][enabled] \_ 2:0:0:6 sdg 8:96 [active][undef] \_ 1:0:0:6 sdu 65:64 [active][undef] mpath5 (36006016067a21a00c4aece82bdd0dd11) dm-6 DGC,RAID 10 [size=3D43G][features=3D1 queue_if_no_path][hwhandler=3D1 emc] \_ round-robin 0 [prio=3D0][active] \_ 2:0:1:5 sdm 8:192 [active][undef] \_ 1:0:1:5 sdaa 65:160 [active][undef] \_ round-robin 0 [prio=3D0][enabled] \_ 2:0:0:5 sdf 8:80 [active][undef] \_ 1:0:0:5 sdt 65:48 [active][undef] mpath4 (36006016067a21a004cf7526fbdd0dd11) dm-7 DGC,RAID 10 [size=3D43G][features=3D1 queue_if_no_path][hwhandler=3D1 emc] \_ round-robin 0 [prio=3D0][active] \_ 2:0:1:4 sdl 8:176 [active][undef] \_ 1:0:1:4 sdz 65:144 [active][undef] \_ round-robin 0 [prio=3D0][enabled] \_ 2:0:0:4 sde 8:64 [active][undef] \_ 1:0:0:4 sds 65:32 [active][undef] mpath3 (36006016067a21a00300e128dbdd0dd11) dm-11 DGC,RAID 10 [size=3D43G][features=3D1 queue_if_no_path][hwhandler=3D1 emc] \_ round-robin 0 [prio=3D0][active] \_ 2:0:0:2 sdc 8:32 [active][undef] \_ 1:0:0:2 sdq 65:0 [active][undef] \_ round-robin 0 [prio=3D0][enabled] \_ 2:0:1:2 sdj 8:144 [active][undef] \_ 1:0:1:2 sdx 65:112 [active][undef] --=20 =E5=90=B4=E5=BE=B7=E6=96=B0 Mark Wu =20 Associate Technical Support Engineer =20 Global Support Services Red Hat China Tel: +86 10 6533 9338