I am doing some benchmarking on EXT4 performance on Compact Flash media.
I have created an ext4 fs with block size of 65536. however I can not
mount it on ubuntu-10.10-netbook-i386. (it is already mounting ext4 fs with 4096 bytes of block sizes)
According to my readings on ext4 it should allow such big block sized
fs. I want to hear your comments.
root@ubuntu:~# mkfs.ext4 -b 65536 /dev/sda3
Warning: blocksize 65536 not usable on most systems.
mke2fs 1.41.12 (17-May-2010)
mkfs.ext4: 65536-byte blocks too big for system (max 4096)
Proceed anyway? (y,n) y
Warning: 65536-byte blocks too big for system (max 4096), forced to continue
Filesystem label=
OS type: Linux
Block size=65536 (log=6)
Fragment size=65536 (log=6)
Stride=0 blocks, Stripe width=0 blocks
19968 inodes, 19830 blocks
991 blocks (5.00%) reserved for the super user
First data block=0
1 block group
65528 blocks per group, 65528 fragments per group
19968 inodes per group
Writing inode tables: done
Creating journal (1024 blocks): done
Writing superblocks and filesystem accounting information: done
This filesystem will be automatically checked every 37 mounts or
180 days, whichever comes first. Use tune2fs -c or -i to override.
root@ubuntu:~# tune2fs -l /dev/sda3
tune2fs 1.41.12 (17-May-2010)
Filesystem volume name: <none>
Last mounted on: <not available>
Filesystem UUID: 4cf3f507-e7b4-463c-be11-5b408097099b
Filesystem magic number: 0xEF53
Filesystem 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
Filesystem flags: signed_directory_hash
Default mount options: (none)
Filesystem state: clean
Errors behavior: Continue
Filesystem OS type: Linux
Inode count: 19968
Block count: 19830
Reserved block count: 991
Free blocks: 18720
Free inodes: 19957
First block: 0
Block size: 65536
Fragment size: 65536
Blocks per group: 65528
Fragments per group: 65528
Inodes per group: 19968
Inode blocks per group: 78
Flex block group size: 16
Filesystem created: Sat Feb 5 14:39:55 2011
Last mount time: n/a
Last write time: Sat Feb 5 14:40:02 2011
Mount count: 0
Maximum mount count: 37
Last checked: Sat Feb 5 14:39:55 2011
Check interval: 15552000 (6 months)
Next check after: Thu Aug 4 14:39:55 2011
Lifetime writes: 70 MB
Reserved blocks uid: 0 (user root)
Reserved blocks gid: 0 (group root)
First inode: 11
Inode size: 256
Required extra isize: 28
Desired extra isize: 28
Journal inode: 8
Default directory hash: half_md4
Directory Hash Seed: afb5b570-9d47-4786-bad2-4aacb3b73516
Journal backup: inode blocks
root@ubuntu:~# mount -t ext4 /dev/sda3 /mnt/
mount: wrong fs type, bad option, bad superblock on /dev/sda3,
missing codepage or helper program, or other error
In some cases useful info is found in syslog - try
dmesg | tail or so
