On sam., 2010-06-26 at 12:13 +0200, jozef janec wrote: > Hello All, > > I'm using device mapper multipath for long time, on SAN storage and I > have detected a few very critical issues. The main is: > > example: > > configure 2 multipath devices (and have friednly names enabled) > > on those two devices create vg and lvol and ctivate it. Than edit the > bindigs file and swap the ids for mpath devices. > > mpatha id1 > mpathb id2 > > to > > mpatha id2 > mpathb id1 > > and restart multipathd > > when you check output from multipath -ll you will see that multipath > swapped the devices behinde the used mpath targets. The result is that > the io operation are directed to wrong lun and the fs is corupted. We > have found workeround and to define aliases for the luns in > multipath.conf. Than the bindigs file is ignored . > > > but this is not fix the best solution is if there will be added some > check if the line in bindings file is correct, or if the mpath target > is used or not, and if it is used don\t allow change it. IS possible > create a patch for this? > > This issue can be happneded for example when you remove bindings file > and you restart the multipath. > > the problem is that you can add lun to the server, it will get mpatha > device name, than second but with scsi id lower as the first one but > because mpatha is already assaigned it will get mpathb. Now when you > remove the bindigs file and restart multipath, multipath will create > new bindigs file not by currect situation which is in dm-multipath but > by scsi ids, and it will swap the luns maps, and activate them . > result corupted fs. > > I think the bext way will be that multipathd should try get the > information from dm-multipath modul, and if they aren't there than by > scsi information. This will avoind create wrong bindings file which > can makes troubles. > > I already restored 3 servers because I lost oracle on alot of > servers. > The bindings file is a database, not a config file. That's why it would best reside in /var than /etc, but the mount ordering problems forced us to move it to /etc. As a database, you wouldn't ever think sane to mangle it freely like you do. user_friendly_names is for people who don't want to name their multipath devices *at all*. If you want user-defined names, you must use aliasing in /etc/multipath.conf. If you have a cluster setup, you must user aliasing to force a consistent device naming across the cluster. > Please could you check if there is possible cerate some patches for > multipathd which will avoid this behavior? > A documentation patch at least. > Thanks > > best regards > > Jozef -- Christophe Varoqui <christophe.varoqui@xxxxxxxxxxx> OpenSVC -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
