Hi, by multiplying block count by block size you get de filesystem size in bytes. Converting into TiB yields a value just shy of 16 TiB (as expected). More precisely 15.99999999627470970153. If the PE size is 4 MiB and my calculations are correct, you would need 16 TiB * 1024 * 1024 / 4 = 4194304 LEs. On Tue, Oct 8, 2013 at 12:06 PM, Sebastian Walter <sebastian.walter@fu-berlin.de> wrote: > Dear List, > > For extending an ext4 partition to some additional TBs, I extended the > underlying logical volume (LV) to fill the entire physical volume of the > disk. This was about 19.4 TB. While trying to extend the ext4 partition > to fill the hole LV, I realized that the ext4 size limit is still at > 16TB. So I set the partition to 16TB. Now I'm wasting space on the LV > which I would like to again be reduced to the minimum size of the > partition (16TB). > > Has anyone an idea to exactly calculate the amount of logical extends > (LE) needed for holding the 16TB partition? I'm sure there are some > bytes needed for overhead, journaling, etc. Maybe we can read it from > one of these outputs: > > This is the partition: > tune2fs -l /dev/storage/storage > tune2fs 1.42.8 (20-Jun-2013) > Filesystem volume name: storage > Last mounted on: /mnt/storage/mnt/storage > Filesystem UUID: 9c05fe79-6a1b-484e-980d-788a6cf5b99c > Filesystem magic number: 0xEF53 > Filesystem revision #: 1 (dynamic) > Filesystem features: has_journal ext_attr resize_inode dir_index > filetype needs_recovery extent sparse_super large_file uninit_bg > Filesystem flags: signed_directory_hash > Default mount options: (none) > Filesystem state: clean > Errors behavior: Continue > Filesystem OS type: Linux > Inode count: 2147483648 > Block count: 4294967295 > Reserved block count: 42909770 > Free blocks: 229845414 > Free inodes: 1929998857 > First block: 0 > Block size: 4096 > Fragment size: 4096 > Blocks per group: 32768 > Fragments per group: 32768 > Inodes per group: 16384 > Inode blocks per group: 512 > Filesystem created: Tue Sep 18 14:50:21 2007 > Last mount time: Tue Oct 8 04:00:16 2013 > Last write time: Tue Oct 8 04:00:16 2013 > Mount count: 24 > Maximum mount count: 36 > Last checked: Sat Oct 6 14:50:58 2012 > Check interval: 15552000 (6 months) > Next check after: Thu Apr 4 14:50:58 2013 > Reserved blocks uid: 0 (user root) > Reserved blocks gid: 0 (group root) > First inode: 11 > Inode size: 128 > Journal inode: 8 > Default directory hash: tea > Directory Hash Seed: 675a96e5-faf3-4576-af10-713007ac8387 > Journal backup: inode blocks > > This is the Logical Volume (vgdisplay -v): > --- Logical volume --- > LV Name /dev/storage/storage > VG Name storage > LV UUID KQtBJN-RXzo-UUhT-MeiR-Ack8-QB2x-g9aPOT > LV Write Access read/write > LV Status available > # open 1 > LV Size 19.18 TB > Current LE 5027838 > Segments 4 > Allocation inherit > Read ahead sectors auto > - currently set to 256 > Block device 253:24 > > And this is the Volume Group (vgdisplay): > --- Volume group --- > VG Name storage > System ID > Format lvm2 > Metadata Areas 2 > Metadata Sequence No 174 > VG Access read/write > VG Status resizable > MAX LV 0 > Cur LV 3 > Open LV 3 > Max PV 0 > Cur PV 2 > Act PV 2 > VG Size 19.77 TB > PE Size 4.00 MB > Total PE 5181438 > Alloc PE / Size 5181438 / 19.77 TB > Free PE / Size 0 / 0 > VG UUID ZalMV7-fZqp-mBA3-aYzi-iADF-VDWV-YIifQr > > What I would like to know is the correct *extents* parameter for > lvreduce. Any help is greatly appreciated! > > Sebastian > > > > _______________________________________________ > 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/ _______________________________________________ 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/
