Description of problem: This is really two bugs: 1. If vdo_pool_autoextend_threshold is turned off, then shouldn't VDO creation warn the user like thin pool creation does? 2. Should all lvcreates after a turned off thin_pool_autoextend_threshold thin pool create continue to warn the user? # Create VDO FIRST, shouldn't there be a "protection against vdo pools running out of space" warning, like with thinpool? [root@hayes-01 ~]# lvcreate --yes --type vdo -n vdovirt -L 10G -V 50G test The VDO volume can address 6 GB in 3 data slabs, each 2 GB. It can grow to address at most 16 TB of physical storage in 8192 slabs. If a larger maximum size might be needed, use bigger slabs. Logical volume "vdovirt" created. # Create Thinpool/virt SECOND, note the warning for "protection against thin pools running out of space" [root@hayes-01 ~]# lvcreate -V 50G -L 10G -T test/pool -n thinvirt Thin pool volume with chunk size 64.00 KiB can address at most <15.88 TiB of data. WARNING: Sum of all thin volume sizes (50.00 GiB) exceeds the size of thin pool test/pool (10.00 GiB). WARNING: You have not turned on protection against thin pools running out of space. WARNING: Set activation/thin_pool_autoextend_threshold below 100 to trigger automatic extension of thin pools before they get full. Logical volume "thinvirt" created. [root@hayes-01 ~]# lvs -a -o +devices,seg_type LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert Devices Type [lvol0_pmspare] test ewi------- 12.00m /dev/sdd1(2560) linear pool test twi-aotz-- 10.00g 0.00 10.64 pool_tdata(0) thin-pool [pool_tdata] test Twi-ao---- 10.00g /dev/sdd1(2563) linear [pool_tmeta] test ewi-ao---- 12.00m /dev/sdi1(0) linear thinvirt test Vwi-a-tz-- 50.00g pool 0.00 thin vdovirt test vwi-a-v--- 50.00g vpool0 0.00 vpool0(0) vdo vpool0 test dwi------- 10.00g 40.04 vpool0_vdata(0) vdo-pool [vpool0_vdata] test Dwi-ao---- 10.00g /dev/sdd1(0) linear [root@hayes-01 ~]# vgremove -f test Logical volume "thinvirt" successfully removed. Logical volume "pool" successfully removed. Logical volume "vdovirt" successfully removed. Volume group "test" successfully removed # Create Thinpool/virt FIRST, note the warning for "protection against thin pools running out of space" [root@hayes-01 ~]# lvcreate -V 50G -L 10G -T test/pool -n thinvirt Thin pool volume with chunk size 64.00 KiB can address at most <15.88 TiB of data. WARNING: Sum of all thin volume sizes (50.00 GiB) exceeds the size of thin pool test/pool (10.00 GiB). WARNING: You have not turned on protection against thin pools running out of space. WARNING: Set activation/thin_pool_autoextend_threshold below 100 to trigger automatic extension of thin pools before they get full. Logical volume "thinvirt" created. # Actually any lv creation from now on will warn about that prior thinpool threshold not being turned on [root@hayes-01 ~]# lvcreate -L100M test WARNING: Sum of all thin volume sizes (50.00 GiB) exceeds the size of thin pools (10.00 GiB). WARNING: You have not turned on protection against thin pools running out of space. WARNING: Set activation/thin_pool_autoextend_threshold below 100 to trigger automatic extension of thin pools before they get full. Logical volume "lvol1" created. # Create VDO THIRD, so now we see multiple thinpool warnings, but not one relevant to the vdo threshold not being on [root@hayes-01 ~]# lvcreate --yes --type vdo -n vdovirt -L 10G -V 50G test WARNING: Sum of all thin volume sizes (50.00 GiB) exceeds the size of thin pools (10.00 GiB). WARNING: You have not turned on protection against thin pools running out of space. WARNING: Set activation/thin_pool_autoextend_threshold below 100 to trigger automatic extension of thin pools before they get full. Wiping vdo signature on /dev/test/vpool0. The VDO volume can address 6 GB in 3 data slabs, each 2 GB. It can grow to address at most 16 TB of physical storage in 8192 slabs. If a larger maximum size might be needed, use bigger slabs. WARNING: Sum of all thin volume sizes (50.00 GiB) exceeds the size of thin pools (10.00 GiB). WARNING: You have not turned on protection against thin pools running out of space. WARNING: Set activation/thin_pool_autoextend_threshold below 100 to trigger automatic extension of thin pools before they get full. Logical volume "vdovirt" created. [root@hayes-01 ~]# lvs -a -o +devices,segtype LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert Devices Type [lvol0_pmspare] test ewi------- 12.00m /dev/sdd1(0) linear lvol1 test -wi-a----- 100.00m /dev/sdd1(5123) linear pool test twi-aotz-- 10.00g 0.00 10.64 pool_tdata(0) thin-pool [pool_tdata] test Twi-ao---- 10.00g /dev/sdd1(3) linear [pool_tmeta] test ewi-ao---- 12.00m /dev/sdi1(0) linear thinvirt test Vwi-a-tz-- 50.00g pool 0.00 thin vdovirt test vwi-a-v--- 50.00g vpool0 0.00 vpool0(0) vdo vpool0 test dwi------- 10.00g 40.04 vpool0_vdata(0) vdo-pool [vpool0_vdata] test Dwi-ao---- 10.00g /dev/sdd1(2563) linear Version-Release number of selected component (if applicable): kernel-4.18.0-372.5.1.el8 BUILT: Mon Mar 28 10:29:22 CDT 2022 lvm2-2.03.14-3.el8 BUILT: Tue Jan 4 14:54:16 CST 2022 lvm2-libs-2.03.14-3.el8 BUILT: Tue Jan 4 14:54:16 CST 2022