Hello, I observed an obscure bug in the current LVM2 tools. Observe this: # dd if=/dev/zero of=testfile bs=1024k count=1 1+0 records in 1+0 records out 1048576 bytes (1,0 MB) copied, 0,009037 seconds, 116 MB/s # losetup /dev/loop4 testfile # pvcreate /dev/loop4 Physical volume "/dev/loop4" successfully created # vgcreate --physicalextentsize=1k test.vg /dev/loop4 Volume group "test.vg" successfully created # lvcreate --name=test.lv --size=832k test.vg Insufficient free extents (640) in volume group test.vg: 832 required # vgremove test.vg Volume group "test.vg" successfully removed # vgcreate --physicalextentsize=1k test.vg /dev/loop4 Volume group "test.vg" successfully created # lvcreate --name=test.lv --size=832k test.vg Logical volume "test.lv" created # I create a file "testfile" of 1024KiB size and view it as /dev/loop4. Then I create a physical volume on /dev/loop4 and a volume group "test.vg" covering that physical volume. The metadata needs the first 192KiB. However, I cannot use the remaining 832KiB for a logical volume. This is the bug. However, if I remove the volume group "test.vg" and once more create it again, now the remaining 832KiB are fully usable. This behaviour is inconsistent. Analyzing the metadata after the first "vgcreate", one can see that the pe_count of the physical volume is too small. It seems that there is space reserved for a second metadata copy at the end of /dev/loop4, however, no second metadata copy is requrested at the invocation of "pvcreate". For me, it is in particuliar important that the first "vgcreate" does not use any extra space at the end of the block device the physical volume lives on, as, in my case, the physical volume contains already data (which is to be made available as a logical volume). ciao, Xuân. _______________________________________________ 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/
