Hello, I have serious problem with Linux multipath connection to our SAN. I think that there is probably a bug in the multipath kernel code. First of all, there is a short hardware and software environment description: Hardware configuration: IBM ESS 2105 SAN storage IBM eServer xSeries x445 (this is Intel based NUMA server) 4 x Xeon MP CPU 2.80GHz 8 GB RAM 2 x QLogic QLA2312 fibre channel adapters Software configuration: Debian GNU/Linux 3.1/testing (sarge) Linux kernel v2.6.6 (plus DM / LVM2 patches) glibc v 2.3.2 mdadm v1.4.0 raidtools2 v1.00.3 I am able to activate Linux multipath connection properly only for firs time. Every time when I try to activate the multipath device(s) again, the system is not able to assemble the multipath device correctly. The result is a multipath device with one path only. Step-by-step description and system diagnostic: 1) Set up a set of block devices into a multipath device: mkraid /dev/md0 handling MD device /dev/md0 analyzing super-block disk 0: /dev/scsi/host2/bus0/target0/lun0/part1, 102534831kB, raid superblock at 102534720kB disk 1: /dev/scsi/host3/bus0/target0/lun0/part1, 102534831kB, raid superblock at 102534720kB Syslog: md: md driver 0.90.0 MAX_MD_DEVS=256, MD_SB_DISKS=27 md: multipath personality registered as nr 7 md: bind<sdb1> md: bind<sdf1> 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) Display details of a multipath device: mdadm --detail /dev/md0 /dev/md0: Version : 00.90.01 Creation Time : Mon Jun 14 12:25:04 2004 Raid Level : multipath Array Size : 102534720 (97.78 GiB 105.00 GB) Raid Devices : 1 Total Devices : 2 Preferred Minor : 0 Persistence : Superblock is persistent Update Time : Mon Jun 14 12:25:04 2004 State : clean, no-errors Active Devices : 1 Working Devices : 2 Failed Devices : 0 Spare Devices : 1 Number Major Minor RaidDevice State 0 8 17 0 active sync /dev/scsi/host2/bus0/target0/lun0/part1 1 8 81 -1 spare /dev/scsi/host3/bus0/target0/lun0/part1 UUID : 1611fd4d:f42482f8:49143747:eee27eff Events : 0.1 3) Turns off an multipath device and unconfigures it: raidstop /dev/md0 Syslog: md: md0 stopped. md: unbind<sdf1> md: export_rdev(sdf1) md: unbind<sdb1> md: export_rdev(sdb1) 4) Activating an existing multipath device: raidstart /dev/md0 Syslog: md: raidstart(pid 1866) used deprecated START_ARRAY ioctl. This will not be supported beyond 2.6 md: autorun ... md: considering sdf1 ... md: adding sdf1 ... md: adding sdb1 ... md: created md0 md: bind<sdb1> md: export_rdev(sdf1) md: running: <sdb1> multipath: array md0 active with 1 out of 1 IO paths md: ... autorun DONE. 5) Display details of a multipath device: mdadm --detail /dev/md0 /dev/md0: Version : 00.90.01 Creation Time : Mon Jun 14 12:25:04 2004 Raid Level : multipath Array Size : 102534720 (97.78 GiB 105.00 GB) Raid Devices : 1 Total Devices : 1 Preferred Minor : 0 Persistence : Superblock is persistent Update Time : Mon Jun 14 14:21:42 2004 State : clean, no-errors Active Devices : 1 Working Devices : 1 Failed Devices : 0 Spare Devices : 0 Number Major Minor RaidDevice State 0 8 17 0 active sync /dev/scsi/host2/bus0/target0/lun0/part1 UUID : 1611fd4d:f42482f8:49143747:eee27eff Events : 0.2 I have tried to test this configuration with kernel from version 2.6.2 to 2.6.6 but with the same error. Any idea? Best regards Marek -- Ing. Marek Uher Linux System Specialist Technology Division T-Mobile Czech Republic a.s. Tomickova 2144/1 149 00 Praha 4 Czech Republic Mobile: (+420) 603 400 728 Office: (+420) 603 607 128 Fax: (+420) 603 600 796 E-mail: marek.uher@xxxxxxxxxxx Web: http://www.t-mobile.cz/ ---------- Disclaimer ---------- Informace obsažené v tomto e-mailu jsou určeny výlučně pro potřeby jeho adresáta. Text nebo přílohy mohou obsahovat utajované informace, informace považované společností T-Mobile za obchodní tajemství, případně jiné informace podléhající ochraně dle příslušných právních předpisů. Pokud Vám tento e-mail byl omylem doručen, zdržte se, prosím, jakékoli manipulace s textem či přílohami, jako je kopírování, přesměrování, zpřístupnění další osobě a podobně. O chybném doručení informujte odesílatele a e-mail včetně příloh vymažte ze svého počítače. The information contained within this e-mail is intended only for the person or entity to which it is addressed. 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