From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?ISO-8859-1?Q?Jaime_Pe=F1alba?= Subject: Re: Multipath problems with 2.6.8.1 Date: Thu, 09 Sep 2004 20:25:17 +0200 Sender: linux-raid-owner@vger.kernel.org Message-ID: <4140A00D.5030406@corenetworks.es> References: <200409091559.i89FxF332735@watkins-home.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <200409091559.i89FxF332735@watkins-home.com> To: linux-raid@vger.kernel.org Cc: neilb@cse.unsw.edu.au List-Id: linux-raid.ids Im using multipath for failover, not for round robin (rr over multipath= =20 isnt supported with the latest stable kernel), also i was wondering=20 about how this should be configured before sending a mail to the list,=20 so i tested both ways (as "2 raid disks" and as "raid disk with spare=20 disk"), the good way is using a spare disk, or i think so. On raidtools= 2=20 there is an example for multipath and they use a spare disk, and it has= =20 sense, because it should act as a spare disk like on a raid 1/5, it use= s=20 the raid disk path, and if it fails, it uses the spare disk path. Anyway here is the output doing it as 2 raid disks 1) create md apache2:~# mdadm --create /dev/md0 --force --level multipath=20 --raid-devices 2 /dev/sdb1 /dev/sdd1 mdadm: array /dev/md0 started. apache2:~# cat /proc/mdstat Personalities : [multipath] md0 : active multipath sdd1[1] sdb1[0] 10485632 blocks [2/2] [UU] =20 unused devices: --------- The output from dmesg md: bind md: bind multipath: array md0 active with 2 out of 2 IO paths And it should be something like this (configured with spare) md: bind md: bind multipath: array md0 active with 1 out of 1 IO paths MULTIPATH conf printout: --- wd:1 rd:1 disk0, o:1, dev:sdb1 MULTIPATH conf printout: --- wd:1 rd:1 disk0, o:1, dev:sdb1 2) stop md apache2:~# mdadm -S /dev/md0 3) start md again apache2:~# mdadm --assemble /dev/md0 /dev/sdb1 /dev/sdd mdadm: failed to add /dev/sdb1 to /dev/md0: Device or resource busy mdadm: /dev/md0 has been started with 2 drives and -1 spares. apache2:~# cat /proc/mdstat Personalities : [multipath] md0 : active multipath sdd1[0] 10485632 blocks [1/1] [U] =20 unused devices: ------------------------------- Superblocks info apache2:~# mdadm -E /dev/sdb1 /dev/sdb1: Magic : a92b4efc Version : 00.90.00 UUID : 57d730b7:49b3d124:b5d30806:127c5bc3 Creation Time : Thu Sep 9 19:49:10 2004 Raid Level : multipath Device Size : 10485632 (10.00 GiB 10.74 GB) Raid Devices : 2 Total Devices : 1 Preferred Minor : 0 Update Time : Thu Sep 9 20:16:37 2004 State : dirty Active Devices : 1 Working Devices : 1 Failed Devices : 1 Spare Devices : 0 Checksum : 9626eafd - correct Events : 0.45 Number Major Minor RaidDevice State this 0 8 49 0 active sync /dev/sdd1 0 0 8 49 0 active sync /dev/sdd1 1 1 0 0 1 faulty removed ----------------------- apache2:~# mdadm -E /dev/sdd1 /dev/sdd1: Magic : a92b4efc Version : 00.90.00 UUID : 57d730b7:49b3d124:b5d30806:127c5bc3 Creation Time : Thu Sep 9 19:49:10 2004 Raid Level : multipath Device Size : 10485632 (10.00 GiB 10.74 GB) Raid Devices : 2 Total Devices : 1 Preferred Minor : 0 Update Time : Thu Sep 9 20:16:37 2004 State : dirty Active Devices : 1 Working Devices : 1 Failed Devices : 1 Spare Devices : 0 Checksum : 9626eafd - correct Events : 0.45 Number Major Minor RaidDevice State this 0 8 49 0 active sync /dev/sdd1 0 0 8 49 0 active sync /dev/sdd1 1 1 0 0 1 faulty removed As you can see both paths points to the same disk, because sdb1 has the= =20 sdd1 superblock, that is the last superblock wroten. Jaime. Guy wrote: >Somehow you confused it! And me. > >You used multipath and spare, but only listed 2 devices. >I don't think a multipath array can have a spare disk. > >Are you sure the 2 paths point to the same disk? > >I have never user multipath, so I am just guessing. > >If you have no data you need to save yet, try this: >mdadm --create /dev/md0 --force --level multipath /dev/sdb1 /dev/sdd1 >or >mdadm --create /dev/md0 --force --level multipath --raid-devices=3D2 /= dev/sdb1 >/dev/sdd1 > >Guy > >-----Original Message----- >From: linux-raid-owner@vger.kernel.org >[mailto:linux-raid-owner@vger.kernel.org] On Behalf Of Jaime Pe=F1alba >Sent: Thursday, September 09, 2004 11:33 AM >To: linux-raid@vger.kernel.org >Cc: neilb@cse.unsw.edu.au >Subject: Multipath problems with 2.6.8.1 > >Hi, > >Im having some troubles with multipath on a 2.6.8.1 linux kernel. > >Im using 2 QLogic 2344 connected to the SAN, i think that my problem i= s=20 >related to superblocks, because when i create a new multipath device, = it=20 >writes the superblock for both disks and really is the same disk troug= ht=20 >two paths. I have else tried to disable persistent superblock, but mda= dm=20 >doesnt support multipath with the build mode. > >Im doing it like this > >1) Start the md >apache1:~/soft/mdadm-1.7.0# mdadm --create /dev/md0 --force --level=20 >multipath --raid-devices=3D1 /dev/sdb1 --spare-devices=3D1 /dev/sdd1 >mdadm: array /dev/md0 started. > >apache1:~/soft/mdadm-1.7.0# cat /proc/mdstat >Personalities : [multipath] >md0 : active multipath sdd1[1] sdb1[0] > 4882304 blocks [1/1] [U] > =20 >unused devices: > >This is ok and runs fine, But superblock is only at /dev/sdd1, so no=20 >remount would be possible, or i think so... > >apache1:~/soft/mdadm-1.7.0# mdadm -E /dev/sdb1 >mdadm: No super block found on /dev/sdb1 (Expected magic a92b4efc, got= =20 >00000000) > >apache1:~/soft/mdadm-1.7.0# mdadm -E /dev/sdd1 >/dev/sdd1: > Magic : a92b4efc > Version : 00.90.00 > UUID : af3395fd:fac2b820:2ca7083c:612864e0 > Creation Time : Thu Sep 9 17:20:43 2004 > Raid Level : multipath > Device Size : 4882304 (4.66 GiB 5.00 GB) > Raid Devices : 1 > Total Devices : 2 >Preferred Minor : 0 > > Update Time : Thu Sep 9 17:20:43 2004 > State : dirty > Active Devices : 1 >Working Devices : 2 > Failed Devices : 0 > Spare Devices : 1 > Checksum : 63bc7489 - correct > Events : 0.36 > > > Number Major Minor RaidDevice State >this 1 8 49 1 spare /dev/sdd1 > 0 0 8 17 0 active sync /dev/sdb1 > 1 1 8 49 1 spare /dev/sdd1 > > > >2) Stop the md >apache1:~/soft/mdadm-1.7.0# mdadm -S /dev/md0 > > >3) Start the md again >apache1:~/soft/mdadm-1.7.0# mdadm --assemble /dev/md0=20 >--uuid=3Daf3395fd:fac2b820:2ca7083c:612864e0 /dev/sdb1 /dev/sdd1 >mdadm: no RAID superblock on /dev/sdb1 >mdadm: /dev/sdb1 has wrong uuid. >mdadm: /dev/md0 has been started with 1 drive. > > >apache1:~/soft/mdadm-1.7.0# cat /proc/mdstat >Personalities : [multipath] >md0 : active multipath sdd1[0] > 4882304 blocks [1/1] [U] > =20 >unused devices: > >Now things arent working very well.... > >apache1:~/soft/mdadm-1.7.0# mdadm --detail /dev/md0 >/dev/md0: > Version : 00.90.01 > Creation Time : Thu Sep 9 17:20:43 2004 > Raid Level : multipath > Array Size : 4882304 (4.66 GiB 5.00 GB) > Raid Devices : 1 > Total Devices : 1 >Preferred Minor : 0 > Persistence : Superblock is persistent > > Update Time : Thu Sep 9 17:26:21 2004 > State : clean > Active Devices : 1 >Working Devices : 1 > Failed Devices : 0 > Spare Devices : 0 > > > Number Major Minor RaidDevice State > 0 8 49 0 active sync /dev/sdd1 > UUID : af3395fd:fac2b820:2ca7083c:612864e0 > Events : 0.37 > > >I would appreciate very much any help with this. > >Thanks, >Jaime. > > =20 > - To unsubscribe from this list: send the line "unsubscribe linux-raid" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html