I have a 4 TB drive and I am missing some space.
It has one partition of 7814035086 sectors:
$ sudo gdisk -l /dev/sdc GPT fdisk (gdisk) version 1.0.1 Partition table scan: MBR: protective BSD: not present APM: not present GPT: present Found valid GPT with protective MBR; using GPT. Disk /dev/sdc: 7814037168 sectors, 3.6 TiB Logical sector size: 512 bytes Disk identifier (GUID): AD8CFC18-1D06-5631-8127-13DCC57E1921 Partition table holds up to 128 entries First usable sector is 34, last usable sector is 7814037134 Partitions will be aligned on 2048-sector boundaries Total free space is 2014 sectors (1007.0 KiB) Number Start (sector) End (sector) Size Code Name 1 2048 7814037134 3.6 TiB 8300 Linux filesystem
That partition is encrypted:
$ sudo cryptsetup status /dev/dm-0 /dev/dm-0 is active and is in use. type: LUKS1 cipher: aes-xts-plain64 keysize: 512 bits device: /dev/sdc1 offset: 4096 sectors size: 7814030991 sectors mode: read/write
It has a size of only 7814030991 caused by the offset. That's ok (only 4096 sectors difference). But now let's check size of the filesystem:
$ df [...] /dev/dm-0 3845576524 3844314380 1245760 100% /media/bak-5
The encrypted device has a size of "7814030991 sectors * 512 byte / 1024 = 3907015495 1K-Blocks". However, the filesystem has a size of only 3845576524 1K-Blocks. That's a difference of 58,59 GiB.
I know that ext4 reserves 5% for root by default, but I already disabled that:
$ sudo tune2fs -l /dev/dm-0 | grep Reserved Reserved block count: 0 Reserved GDT blocks: 791 Reserved blocks uid: 0 (user root) Reserved blocks gid: 0 (group root)
How can I use that "missing" 58 GiB?
PS: It's a rarely used backup drive so don't worry about disabling the 5% reserved area :)