Hi all, I'm testing a storage prototype that combines iscsi, multipath, and lvm. The model allows iscsi client to attach/detach multiple iscsi LUNs exposed by storage server. Here are the steps for client to attach to server storage: 1. iscsi initiator creates multiple LUNs (local at /dev/sde, /dev/sdf, etc), for example: $ iscsiadm -m node -p a.b.c.d:3260 -T xxxx -l 2.dm-multipath to create a multipath device for each of the iscsi LUN (/dev/mapper/xyz, etc), for example: $ multipath -r /dev/sde In current test every multipath device has only one iscsi lun such as: 36000000076c10ff42e1fa3dd909bb3cf dm-47 HCD,VIRTUAL-DISK size=140G features='1 queue_if_no_path' hwhandler='0' wp=rw `-+- policy='round-robin 0' prio=1 status=active `- 138:0:0:1 sdae 65:224 active ready running 3. create a volume group that combines several multipath devices together. $ pvcreate -f -y /dev/mapper/xxx $ vgcreate vol1 /dev/mapper/xxx /dev/mapper/yyy /dev/mapper/zzz After repeating step 1/2/3 to create several volume groups, I hit couple of error scenarios as listed below. These errors seem to happen at random order: error 1: Physical volume '/dev/mapper/360000000557b690283509c3709c4fc0b' is already in volume group 'vol8', Unable to add physical volume '/dev/mapper/360000000557b690283509c3709c4fc0b' to volume group 'vol14'. error 2: Found duplicate PV W9rMQ0GuoNw9rnzK8x47OVEY044A2mgT: using /dev/mapper/360000000a1d91e849f66dd53a61d8fa9 not /dev/mapper/360000000e2ddd2a9380e9159902d9f73, Using duplicate PV /dev/mapper/360000000a1d91e849f66dd53a61d8fa9 without holders, replacing /dev/mapper/360000000e2ddd2a9380e9159902d9f73, error 3: Can't open /dev/mapper/360000000e2ddd2a9380e9159902d9f73 exclusively. Mounted filesystem? Unable to add physical volume '/dev/mapper/360000000e2ddd2a9380e9159902d9f73' to volume group 'vol2'. I'm very sure all PVs are freshly created and there is no duplicated PVs at all. =========== /etc/multipath.conf: defaults { path_grouping_policy failover polling_interval 3 path_selector "round-robin 0" features "1 queue_if_no_path" } ============ lvm.conf: I use config coming from lvm2 package. The only change is: auto_activation_volume_list = [] =============== Here is the software pkg version: Ubuntu 16.04 lvm2 2.02.133-1ubuntu10 multipath-tools: 0.5.0+git1.656f8865-5ubuntu2.4 open-iscsi: 2.02.133-1ubuntu10 _______________________________________________ linux-lvm mailing list linux-lvm@redhat.com https://www.redhat.com/mailman/listinfo/linux-lvm read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/