On jeu, 2005-07-21 at 16:31 +0200, Philipp Niemann wrote: > Hello list, nice to meet you. > > As I am new to the list I am not quite shure if the topic is correct, > but... > > Around here I have two EMC Clariion 4500 Storage Arrays, two Brocade Silkworms > each building a fabric, and two QLogic 2340 HBA in my PC. For now I am > using debian stable (sarge) with a vanilla kernel-2.6.12.3 compiled with > all I can get from the md/devmapper part of config. > > I want the OS to use the two HBAs for path failover. The Clariion is an > activce/passive device. > > I use the multipath-tools written by Christophe Varoqui and others, > version 0.4.2.4-2 as packaged with debian. There is a more up to date > one on the project homepage but I haved bothered yet. > > Is this the right list to ask for help/suggestions? What details would > you like to have then? If not the right list, where to post? > > More details: > > HBA1 is connected to Clariion1_SPA and Clariion2_SPA via fabric1 > HBA2 is connected to Clariion1_SPB and Clariion2_SPB via fabric2 > > I have the devices in /proc/partitions (total of 5 LUNs configured, each > with 2 path makes 10 devices in /proc/partitions) > > I have multipath configured like this: > > # multipath -lv2 # should be group-by-node-name policy > 3600601602001f1a665653dbe010465c5 > [size=22 GB][features="0"][hwhandler="0"] > \_ round-robin 0 [enabled][first] > \_ 6:0:0:0 sda 8:0 [ready ][active] > \_ 7:0:1:0 sdh 8:112 [faulty][active] > > 360060160200161a037f90d75dfca84f7 > [size=20 GB][features="0"][hwhandler="0"] > \_ round-robin 0 [active][first] > \_ 6:0:1:1 sde 8:64 [faulty][active] > \_ 7:0:0:1 sdg 8:96 [ready ][active] > > 3600601602001f1a600a524d18275c0b2 > [size=20 GB][features="0"][hwhandler="0"] > \_ round-robin 0 [enabled][first] > \_ 6:0:0:1 sdb 8:16 [ready ][active] > \_ 7:0:1:1 sdi 8:128 [faulty][active] > > 3600601602001f1a6e0c6fdbae081bd89 > [size=20 GB][features="0"][hwhandler="0"] > \_ round-robin 0 [enabled][first] > \_ 6:0:0:2 sdc 8:32 [faulty][active] > \_ 7:0:1:2 sdj 8:144 [ready ][active] > > 360060160200161a06215f38ffbb2d6e9 > [size=20 GB][features="0"][hwhandler="0"] > \_ round-robin 0 [enabled][first] > \_ 6:0:1:0 sdd 8:48 [faulty][active] > \_ 7:0:0:0 sdf 8:80 [ready ][active] > > > I think this doesn't look too bad. Ready/Faulty match the default owner for the > LUN on the Clariion. I am able to create a filesystem say on > 360060160200161a037f90d75dfca84f7, which might appear as dm-4 in /proc/partitions > It does *not* look good. You ought to have 2 paths group per multipath. One for active paths, the other for inactive paths. As you'll see this is why the failover does not work for you. > BTW: Anyone to know what "hwhandler" tells me? Can I change it? Same for > "features". The "hardware handler" is an optional additional kernel module used to trigger a specific operation when a new Path Group get activated. This is how the host will ask your Clariion controler to activate the inactive paths, for example. So yes, you need hwhandler="1 emc". "0" meaning no hwhandler at all. > BTW2: I'd prefer to use "emc" instead of "round-robin". How? > I concluded something like that might be possible as dm-round-robin > and dm-emc exist > bzz. round-robin is the io speading policy, whereas "emc" is a hwhandler. Different beast. > I am able to mount that filesystem and to create files on it. I prefer doing something > like dd if=/dev/zero of=/mnt/test bs=1024 count=$((1024*1024*19)). That way I have > plenty of time to do some failover tests. > > My problem (finally): If I pull the cable establishing the path to sdg, I get > almost immediate hard IO errors, corrupting the filesystem. The devmapper > won't switch to the second path, though it recognizes the failing > disk sdg and disables the path 8:96. How do I do that properly? > You should now know what to do :/ Regards, -- christophe varoqui <christophe.varoqui@xxxxxxx>
