Change the number of reserved filesystem blocks.
Default number of reserved filesystem blocks
Display current values of the filesystem parameters.
$ sudo tune2fs -l /dev/sda3 tune2fs 1.44.1 (24-Mar-2018) Filesystem volume name: <none> Last mounted on: / Filesystem UUID: 0db04d02-6e6b-491d-a13e-f1e00c9a8cd1 Filesystem magic number: 0xEF53 Filesystem revision #: 1 (dynamic) Filesystem features: has_journal ext_attr resize_inode dir_index filetype needs_recovery extent 64bit flex_bg sparse_super large_file huge_file dir_nlink extra_isize metadata_csum Filesystem flags: signed_directory_hash Default mount options: user_xattr acl Filesystem state: clean Errors behavior: Continue Filesystem OS type: Linux Inode count: 15491072 Block count: 61932544 Reserved block count: 3096627 Free blocks: 12697518 Free inodes: 13987896 First block: 0 Block size: 4096 Fragment size: 4096 Group descriptor size: 64 Reserved GDT blocks: 1024 Blocks per group: 32768 Fragments per group: 32768 Inodes per group: 8192 Inode blocks per group: 512 Flex block group size: 16 Filesystem created: Thu Jun 14 20:04:09 2018 Last mount time: Wed Sep 18 00:10:49 2019 Last write time: Wed Sep 18 00:10:48 2019 Mount count: 25 Maximum mount count: -1 Last checked: Thu Jun 14 20:04:09 2018 Check interval: 0 (<none>) Lifetime writes: 4091 GB Reserved blocks uid: 0 (user root) Reserved blocks gid: 0 (group root) First inode: 11 Inode size: 256 Required extra isize: 32 Desired extra isize: 32 Journal inode: 8 First orphan inode: 7602256 Default directory hash: half_md4 Directory Hash Seed: b2be8da3-dcad-4029-b282-05c63e4890ab Journal backup: inode blocks Checksum type: crc32c Checksum: 0xcc7e4256
This filesystem is using 4096 block size, it has 61932544 blocks, including 3096627 reserved ones.
Report of the filesystem disk space usage will be slightly different, but there is nothing to worry about as it takes into consideration blocks used by the journal and inode blocks.
$ df --block-size=4K / Filesystem Type 4K-blocks Used Available Use% Mounted on /dev/sda3 ext4 60697961 44235478 13361760 77% /
$ df --human-readable / Filesystem Type Size Used Avail Use% Mounted on /dev/sda3 ext4 232G 169G 53G 77% /
By default the number of reserved blocks is set to 5%.
$ echo "61932544*5/100" | bc 3096627
In this case it will be around 11GB.
$ echo "(3096627*4096)/1024^3" | bc 11
Alter the number of reserved filesystem blocks by a percentage
Increase number of reserved blocks to 10%.
$ sudo tune2fs -m 10 /dev/sda3 tune2fs 1.44.1 (24-Mar-2018) Setting reserved blocks percentage to 10% (6193254 blocks)
In this case it will be around 23GB or 24192MB to be more exact.
$ echo "(6193254*4096)/1024^3" | bc 23
$ echo "(6193254*4096)/1024^2" | bc 24192
Display altered values of the filesystem parameters.
$ sudo tune2fs -l /dev/sda3 tune2fs 1.44.1 (24-Mar-2018) Filesystem volume name: <none> Last mounted on: / Filesystem UUID: 0db04d02-6e6b-491d-a13e-f1e00c9a8cd1 Filesystem magic number: 0xEF53 Filesystem revision #: 1 (dynamic) Filesystem features: has_journal ext_attr resize_inode dir_index filetype needs_recovery extent 64bit flex_bg sparse_super large_file huge_file dir_nlink extra_isize metadata_csum Filesystem flags: signed_directory_hash Default mount options: user_xattr acl Filesystem state: clean Errors behavior: Continue Filesystem OS type: Linux Inode count: 15491072 Block count: 61932544 Reserved block count: 6193254 Free blocks: 12697518 Free inodes: 13987896 First block: 0 Block size: 4096 Fragment size: 4096 Group descriptor size: 64 Reserved GDT blocks: 1024 Blocks per group: 32768 Fragments per group: 32768 Inodes per group: 8192 Inode blocks per group: 512 Flex block group size: 16 Filesystem created: Thu Jun 14 20:04:09 2018 Last mount time: Wed Sep 18 00:10:49 2019 Last write time: Wed Nov 20 01:14:22 2019 Mount count: 25 Maximum mount count: -1 Last checked: Thu Jun 14 20:04:09 2018 Check interval: 0 (<none>) Lifetime writes: 4091 GB Reserved blocks uid: 0 (user root) Reserved blocks gid: 0 (group root) First inode: 11 Inode size: 256 Required extra isize: 32 Desired extra isize: 32 Journal inode: 8 First orphan inode: 7602256 Default directory hash: half_md4 Directory Hash Seed: b2be8da3-dcad-4029-b282-05c63e4890ab Journal backup: inode blocks Checksum type: crc32c Checksum: 0x39f657c8
Do not reserve any filesystem blocks.
Set the number of reserved blocks to 0%.
$ sudo tune2fs -m 0 /dev/sda3 tune2fs 1.44.1 (24-Mar-2018) Setting reserved blocks percentage to 0% (0 blocks)
Set the number of reserved blocks to `` blocks.
$ sudo tune2fs -r 0 /dev/sda3 tune2fs 1.44.1 (24-Mar-2018) Setting reserved blocks count to 0
Display altered values of the filesystem parameters.
$ sudo tune2fs -l /dev/sda3 tune2fs 1.44.1 (24-Mar-2018) Filesystem volume name: <none> Last mounted on: / Filesystem UUID: 0db04d02-6e6b-491d-a13e-f1e00c9a8cd1 Filesystem magic number: 0xEF53 Filesystem revision #: 1 (dynamic) Filesystem features: has_journal ext_attr resize_inode dir_index filetype needs_recovery extent 64bit flex_bg sparse_super large_file huge_file dir_nlink extra_isize metadata_csum Filesystem flags: signed_directory_hash Default mount options: user_xattr acl Filesystem state: clean Errors behavior: Continue Filesystem OS type: Linux Inode count: 15491072 Block count: 61932544 Reserved block count: 0 Free blocks: 12697518 Free inodes: 13987896 First block: 0 Block size: 4096 Fragment size: 4096 Group descriptor size: 64 Reserved GDT blocks: 1024 Blocks per group: 32768 Fragments per group: 32768 Inodes per group: 8192 Inode blocks per group: 512 Flex block group size: 16 Filesystem created: Thu Jun 14 20:04:09 2018 Last mount time: Wed Sep 18 00:10:49 2019 Last write time: Wed Nov 20 01:16:46 2019 Mount count: 25 Maximum mount count: -1 Last checked: Thu Jun 14 20:04:09 2018 Check interval: 0 (<none>) Lifetime writes: 4091 GB Reserved blocks uid: 0 (user root) Reserved blocks gid: 0 (group root) First inode: 11 Inode size: 256 Required extra isize: 32 Desired extra isize: 32 Journal inode: 8 First orphan inode: 7602256 Default directory hash: half_md4 Directory Hash Seed: b2be8da3-dcad-4029-b282-05c63e4890ab Journal backup: inode blocks Checksum type: crc32c Checksum: 0x39f657c8
Alter the number of reserved filesystem blocks by a block count
Calculate the number of blocks for 10GB
$ echo "(10*1024^3)/4096" | bc 2621440
Set the number of reserved blocks to 2621440.
$ sudo tune2fs -r 2621440 /dev/sda3 tune2fs 1.44.1 (24-Mar-2018) Setting reserved blocks count to 2621440
Display altered values of the filesystem parameters.
$ sudo tune2fs -l /dev/sda3 tune2fs 1.44.1 (24-Mar-2018) Filesystem volume name: <none> Last mounted on: / Filesystem UUID: 0db04d02-6e6b-491d-a13e-f1e00c9a8cd1 Filesystem magic number: 0xEF53 Filesystem revision #: 1 (dynamic) Filesystem features: has_journal ext_attr resize_inode dir_index filetype needs_recovery extent 64bit flex_bg sparse_super large_file huge_file dir_nlink extra_isize metadata_csum Filesystem flags: signed_directory_hash Default mount options: user_xattr acl Filesystem state: clean Errors behavior: Continue Filesystem OS type: Linux Inode count: 15491072 Block count: 61932544 Reserved block count: 2621440 Free blocks: 12697518 Free inodes: 13987896 First block: 0 Block size: 4096 Fragment size: 4096 Group descriptor size: 64 Reserved GDT blocks: 1024 Blocks per group: 32768 Fragments per group: 32768 Inodes per group: 8192 Inode blocks per group: 512 Flex block group size: 16 Filesystem created: Thu Jun 14 20:04:09 2018 Last mount time: Wed Sep 18 00:10:49 2019 Last write time: Wed Nov 20 01:19:58 2019 Mount count: 25 Maximum mount count: -1 Last checked: Thu Jun 14 20:04:09 2018 Check interval: 0 (<none>) Lifetime writes: 4091 GB Reserved blocks uid: 0 (user root) Reserved blocks gid: 0 (group root) First inode: 11 Inode size: 256 Required extra isize: 32 Desired extra isize: 32 Journal inode: 8 First orphan inode: 7602256 Default directory hash: half_md4 Directory Hash Seed: b2be8da3-dcad-4029-b282-05c63e4890ab Journal backup: inode blocks Checksum type: crc32c Checksum: 0x39f657c8