From mboxrd@z Thu Jan 1 00:00:00 1970 From: Erez Zilber Subject: Re: Running open-iscsi with device mapper hangs Date: Tue, 09 May 2006 17:14:19 +0300 Message-ID: <4460A3BB.9010703@voltaire.com> References: <4460A074.6030805@voltaire.com> Reply-To: device-mapper development Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: quoted-printable Return-path: In-Reply-To: <4460A074.6030805@voltaire.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com To: open-iscsi@googlegroups.com Cc: device-mapper development List-Id: dm-devel.ids Erez Zilber wrote: >Hi, > >I'm trying to run open-iscsi with the multipath tool. I was able to=20 >create a scenario in which the initiator machine hangs: > >My initiator runs on a SLES 10 beta 8 machine. The db contains 2 targets= : >iscsiadm -m node >[83347a] 192.168.10.106:3260,1 iqn.2005-12.com.voltaire.206000C0FF07C1D1 >[030479] 192.168.10.105:3260,1 iqn.2005-12.com.voltaire.206000C0FF07C1D1 > >Loading the dm modules: > >salt:~ # modprobe dm-mod; modprobe dm-multipath > >I start the initiator: > >salt:~ # /etc/init.d/open-iscsi start >Starting iSCSI initiator service: done >Logging into iqn.2005-12.com.voltaire.206000C0FF07C1D1: done >Logging into iqn.2005-12.com.voltaire.206000C0FF07C1D1: done > >salt:~ # sg_map -i -x >/dev/sg0 0 0 0 0 0 /dev/sda DotHill SANnet II FC 411I >/dev/sg1 1 0 0 0 0 /dev/sdb DotHill SANnet II FC 411I > >Now, I start the multipath daemon: > >salt:~ # ls /dev/mapper/ >control >salt:~ # multipathd >salt:~ # ls /dev/mapper/ >control mpath0 >salt:~ # multipath -l >mpath0 (3600c0ff00000000007c1d121c397f503) >[size=3D10 GB][features=3D0][hwhandler=3D0] >\_ round-robin 0 [prio=3D0][active] >\_ 0:0:0:0 sda 8:0 [active][undef] >\_ round-robin 0 [prio=3D0][enabled] >\_ 1:0:0:0 sdb 8:16 [active][undef] > >Running some traffic: > >salt:~ # dd if=3D/dev/mapper/mpath0 of=3D/dev/null count=3D500000 >500000+0 records in >500000+0 records out >256000000 bytes (256 MB) copied, 9.54608 seconds, 26.8 MB/s > >Now, I disconnect (unplug the cable) the target which is represented by=20 >/dev/sda and run another dd command: > >salt:~ # dd if=3D/dev/mapper/mpath0 of=3D/dev/null count=3D500000 >500000+0 records in >500000+0 records out >256000000 bytes (256 MB) copied, 199.601 seconds, 1.3 MB/s > >Now, the 1st priority group has failed: > >salt:~ # multipath -l >mpath0 (3600c0ff00000000007c1d121c397f503) >[size=3D10 GB][features=3D0][hwhandler=3D0] >\_ round-robin 0 [prio=3D0][enabled] >\_ 0:0:0:0 sda 8:0 [failed][faulty] >\_ round-robin 0 [prio=3D0][active] >\_ 1:0:0:0 sdb 8:16 [active][undef] > >I reconnect the target and it's back to life: > >salt:~ # multipath -l >mpath0 (3600c0ff00000000007c1d121c397f503) >[size=3D10 GB][features=3D0][hwhandler=3D0] >\_ round-robin 0 [prio=3D0][enabled] >\_ 0:0:0:0 sda 8:0 [active][undef] >\_ round-robin 0 [prio=3D0][active] >\_ 1:0:0:0 sdb 8:16 [active][undef] > >I stop the initiator and the machine hangs: > >salt:~ # /etc/init.d/open-iscsi stop >Logging out from iqn.2005-12.com.voltaire.206000C0FF07C1D1: done >Logging out from iqn.2005-12.com.voltaire.206000C0FF07C1D1: (now the=20 >machine is dead) > >I know that the device mapper was tested in the past. Was this scenario=20 >tested? Is anyone able to reproduce this behavior? I was able to=20 >reproduce it 5 times in a row. > >Thanks > =20 > BTW - a very similar test without the device mapper works ok. I've=20 disconnected /dev/sda, tried running a dd command using /dev/sda, then I=20 reconnected /dev/sda and the command completed. When I stopped the=20 initiator, the machine didn't hang. Erez --=20 ____________________________________________________________ Erez Zilber | 972-9-971-7689 Software Engineer, Storage Team Voltaire =96 _The Grid Backbone_ __ www.voltaire.com =20