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Description of problem: I have a system with multiple iSCSI connexions. On all of these (multipathed) device, I have created a Physical Volume, then a Volume Group and through virt-manager I have created the Logical Volume. Now after a bit of handling these volume group, I have two problems : - the hypervisor sees a volume group that is actually defined within one of my guest but it doesn't sees the underlying physical volume Therefore, each pv*, vg* or lv* command returns a warning with : Couldn't find device with uuid SYYswn-VBES-9IX8-5h8V-QAyP-Coa0-qBAvvY. But following to that I have a duplicate Physical volume found within the system. That isn't the real problem , but I wanted to check with the tool system-config-lvm. At launch, the interface is scanning the LVM and the crases Version-Release number of selected component (if applicable): System-config-lvm is in version system-config-lvm-1.1.12-7.el6.noarch How reproducible: I can reproduce it on my server, but I can't tell exactly how to. Steps to Reproduce: 1. Have a LVM that behaves strangely (by seeing VG within a guest) 2. Launch system-config-lvm Actual results: system-config-lvm crashes with the following trace : [root@castafiore ~]# system-config-lvm Traceback (most recent call last): File "/usr/sbin/system-config-lvm", line 172, in <module> runFullGUI() File "/usr/sbin/system-config-lvm", line 157, in runFullGUI blvm = baselvm(glade_xml, app) File "/usr/sbin/system-config-lvm", line 105, in __init__ self.volume_tab_view = Volume_Tab_View(glade_xml, self.lvmm, self.main_win) File "/usr/share/system-config-lvm/Volume_Tab_View.py", line 133, in __init__ self.prepare_tree() File "/usr/share/system-config-lvm/Volume_Tab_View.py", line 214, in prepare_tree self.model_factory.reload() File "/usr/share/system-config-lvm/lvm_model.py", line 175, in reload self.__set_LVs_props() # has to come after link_mirrors File "/usr/share/system-config-lvm/lvm_model.py", line 813, in __set_LVs_props lv.set_properties(self.__get_data_for_LV(lv)) File "/usr/share/system-config-lvm/lvm_model.py", line 869, in __get_data_for_LV text_list.append(self.__getFS(lv.get_path())) File "/usr/share/system-config-lvm/lvm_model.py", line 1021, in __getFS if path_list[0].getPartition()[1].id == ID_EMPTY: TypeError: 'NoneType' object is unsubscriptable Expected results: system-config-lvm should be running fine. Additional info: I wonder how the host can see the VG within the guest machine.
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This looks like a problem in something different. Both my tests are working as expected and system-config-lvm is working. Unit test for missing PV: dd if=/dev/zero of=loopA count=30000 bs=1024 dd if=/dev/zero of=loopB count=30000 bs=1024 losetup -f loop; pvcreate /dev/loop0 /dev/loop1; vgcreate foo /dev/loop0; lvcreate foo -n goo -l 10%FREE losetup -d /dev/loop1 run system-config-lvm Unit test for duplicate PV: dd if=/dev/zero of=loopA count=30000 bs=1024 losetup -f loopA pvcreate /dev/loop0 vgcreate foo /dev/loop0 lvcreate -n hugo foo -l 10%FREE vgchange -an foo cp loopA loopB losetup -f loopB pvscan run system-config-lvm
Indeed, the situation I experienced was different. (I'll try to reproduce it exactly). I my case the problem is that the host OS is seeing the virtual VG that are within a VM. Here are the bigger step to reproduce : - Install a RHEL with Virtualization Tools (leave some place in the VG ideally) - Create a VG and carve a LV from it. - Set this LV to be the storage of a Virtual Machine (I used KVM) - Boot the VM and at install set a standard LVM layer. When using pvscan (or vgscan) the host server see the VG of the guest, but apparently can't see the PV. Please, note that the VG I created for the VMs are located on iSCSI storage I believe I could exactly reproduce the setup, I'll post it here. Bruno
Another possibility is that the bug is due to PV nesting within LVs. There is only limited support for this scenario and it is strongly suggested to use lvm.conf device filters to avoid this whenever possible. (You should exclude any LVs you have from LVM PV scanning. The documentation and examples in your lvm.conf should give you enough guidance.) This is especially true when you are dealing with virtual machine images.
Hi, Here is my filter from lvm.conf : filter = [ "a|/dev/sda2|","a|/dev/mapper/.*|", "r|.*|" ] The /dev/sda2 is the main storage for local installation, all others disks are connected through iSCSI and multi-pathed. I noticed something while analysing the missings PV. It appears only when the virtual machine is using two PV grouped together within one VG. It is usually a scenario when you want to increase the size of the storage for the vm, and you add a second PV, then group ip within a VG (then resize the fs). Bruno
Hi Bruno, From looking at your filter (I assume this is in the host, not the guest right?), and your .cache file: filter = [ "a|/dev/sda2|","a|/dev/mapper/.*|", "r|.*|" ] It seems clear the filter will allow the host to scan the logical volumes which were assigned to the guest (The 'a|/dev/mapper/.*|' part will pick up all the multipath paths, as well as logical volumes). Since this is allowed, these logical volumes will be seen as "PVs" as well, since they've been exported to the guest, and inside the guest they were initialized as PVs. I don't think this is what you intend. To avoid this you should set the filter more restrictively, so that the logical volumes exported to the guest are not scanned by any lvm commands in the host. To see which devices lvm commands will scan, look at the contents of the /etc/lvm/cache/.cache file. If it contains any of the logical volumes exported to the hosts, it probably needs adjusted. One common adjustment is as follows: For multipath LUNs using user_friendly_names, add "a|/dev/mapper/mpath.*|" instead of "a|/dev/mapper/.*|" You should probably look at https://access.redhat.com/kb/docs/DOC-2991 for configuration of the filter properly. Even still, this should not cause system-config-lvm to crash.
Hi Dave, I agree the filter should be set more restrictively but I don't use friendly names in the multipath configuration, so I can't use "a|/dev/mapper/mpath.*|", but I could even be explicit by defining each multipath volume like this : filter = [ "a|/dev/sda2|", "a|/dev/mapper/alias1|", "a|/dev/mapper/alias2|", "r|.*|" ] I guess it would not really impact the performance of the scanning since it is done only once at a time. Bruno
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