Hello Zdenek, I am frequently hitting issues when trying to create a new VG on a PV that had existing VG. (This PV is usually an MD raid0 or raid1 device). I am wondering what is the correct procedure to completely wipe out any remains of LVM signatures from a PV, and initialize the PV afresh? Here is what I do: for each new VG, I use a new GUID as part of its name, to avoid VG name conflicts. To try to handle the old VG, the VG creation code first calls lvm_vg_name_from_device(pv_name). If it founds a VG there and succeeds to open it, it goes over its LVs, and tries to deactivate them and then removes them. Finally, the code removes the old VG itself. In some cases, however, the code fails to open the old VG, so it proceeds. Next thing I call pvcreate (fork/exec) to initialize the PV (I always use --force twice). After this is completed, I do lvm_scan(), because pvcreate ran in a different context, and I want to refresh the LVM cache of my process (makes sense?). Finally, I do lvm_vg_create, lvm_vg_extend, lvm_vg_write. Sometimes I hit problems like following: - I want to create a VG named pool_9644BCB5D4704164976DBD85E471EAAA with a single PV (/dev/md2) - lvm_vg_name_from_device() returns the name of an old VG: pool_6A5C57F39FFB4C609D5438D1FCCCDDF0 - lvm_vg_open() fails to open this old VG - pvcreate(/dev/md2) output: STDOUT: Physical volume "/dev/md2" successfully created STDERR: Couldn't find device with uuid NCtRLE-1ffs-GLaH-MYNS-d1hk-ikAt-7dbhm0. Writing physical volume data to disk "/dev/md2" After lvm_scan(),lvm_vg_create(pool_9644BCB5D4704164976DBD85E471EAAA), lvm_vg_extend(), lvm_vg_write(), the syslog shows: Wiping cache of LVM-capable devices get_pv_from_vg_by_id: vg_read_internal failed to read VG pool_74C7247AE06F4B7DAC557D9A1842EEBD Adding physical volume '/dev/md2' to volume group 'pool_9644BCB5D4704164976DBD85E471EAAA' Creating directory "/etc/lvm/archive" Archiving volume group "pool_9644BCB5D4704164976DBD85E471EAAA" metadata (seqno 0). While pool_74C7247AE06F4B7DAC557D9A1842EEBD is yet some other old VG. At this point the VG seems to be created ok. But later, when I try to create first LV, syslog shows: Wiping cache of LVM-capable devices Couldn't find device with uuid NCtRLE-1ffs-GLaH-MYNS-d1hk-ikAt-7dbhm0. Couldn't find device with uuid NCtRLE-1ffs-GLaH-MYNS-d1hk-ikAt-7dbhm0. There are 1 physical volumes missing. Cannot change VG pool_9644BCB5D4704164976DBD85E471EAAA while PVs are missing. Consider vgreduce --removemissing. Why does LVM think that my new VG has PVs missing? Probably it thinks that this PV belongs to another VG? But it looks like LVM agreed to add the PV to the new VG. Is there anything else I am missing? Thanks, Alex. _______________________________________________ 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/
