Eu *acho* que nenhum sistema de arquivos Linux deixa usar um tamanho de bloco maior do que o tamanho de uma página (hardware), que é 4 KiB em x86 (sem PSE). Você poderia tentar a opção bigalloc do EXT4, que suporta clusters de até 256 MiB. Contudo, fique avisado que não é um recurso dos mais testados e está disponível apenas a partir do kernel 3.2 e e2fsprogs 1.42. Ou seja, terá que ser o CentOS 7.
# mkfs.ext4 -C 8K -O bigalloc /dev/sda1mke2fs 1.42.12 (29-Aug-2014)Warning: the bigalloc feature is still under developmentSee https://ext4.wiki.kernel.org/index.php/Bigalloc for more informationCreating filesystem with 52428800 4k blocks and 13107200 inodesFilesystem UUID: xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxxSuperblock backups stored on blocks: 65536, 196608, 327680, 458752, 589824, 1638400, 1769472, 3211264, 5308416, 8192000, 15925248, 22478848, 40960000, 47775744Allocating group tables: doneWriting inode tables: doneCreating journal (32768 blocks): doneWriting superblocks and filesystem accounting information: done
# tune2fs -l /dev/sda1tune2fs 1.42.12 (29-Aug-2014)Filesystem volume name: <none>Last mounted on: <not available>Filesystem UUID: xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxxFilesystem magic number: 0xEF53Filesystem revision #: 1 (dynamic)Filesystem features: has_journal ext_attr resize_inode dir_index filetype extent flex_bg sparse_super large_file huge_file uninit_bg dir_nlink extra_isize bigallocFilesystem flags: signed_directory_hashDefault mount options: user_xattr aclFilesystem state: cleanErrors behavior: ContinueFilesystem OS type: LinuxInode count: 13107200Block count: 52428800Reserved block count: 2621440Free blocks: 51567514Free inodes: 13107189First block: 0Block size: 4096Cluster size: 8192Reserved GDT blocks: 505Blocks per group: 65536Clusters per group: 32768Inodes per group: 16384Inode blocks per group: 1024Flex block group size: 16Filesystem created: Wed Dec 17 20:28:52 2014Last mount time: n/aLast write time: Wed Dec 17 20:28:53 2014Mount count: 0Maximum mount count: -1Last checked: Wed Dec 17 20:28:52 2014Check interval: 0 (<none>)Lifetime writes: 130 MBReserved blocks uid: 0 (user root)Reserved blocks gid: 0 (group root)First inode: 11Inode size: 256Required extra isize: 28Desired extra isize: 28Journal inode: 8Default directory hash: half_md4Directory Hash Seed: 092f8831-b0d6-45bb-8d0f-d51841f8b0d1Journal backup: inode blocks"Cluster size: 8192"