Neither specifying inode ratio nor inode quantity seems to have an effect on mkfs.ext2

Bogomips_ · 01-22-2017, 05:48 PM

Creating Partition to Archive Large files of type Video/ISO. Partition of 302 GiB to have ext2 filesystem, using Kernel 4.9.0. Expect to fit about 350 files in, at most 500. So start with

Inode every 64M

Code:

root@porteus:/home/guest# mkfs.ext2 -b 4096 -m 0 -i 67108864 /dev/sdb3
mke2fs 1.43.1 (08-Jun-2016)
Creating filesystem with 79167488 4k blocks and 38656 inodes
Filesystem UUID: 3aab194d-8ef5-4905-bbdc-748fdf507674
Superblock backups stored on blocks: 
        32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208, 
        4096000, 7962624, 11239424, 20480000, 23887872, 71663616, 78675968

Allocating group tables: done                            
Writing inode tables: done                            
Writing superblocks and filesystem accounting information: done

Expect just 16 x 302 = 4832 inodes. However have 38656 inodes, giving 8M per inode.

Inode every 512M

Code:

root@porteus:/home/guest# mkfs.ext2 -b 4096 -m 0 -i 536870912 /dev/sdb3
mkfs.ext2: invalid inode ratio 536870912 (min 1024/max 67108864)

Inode every 48M

Code:

root@porteus:/home/guest# mkfs.ext2 -b 4096 -m0 -i50331648 /dev/sdb3                    
mke2fs 1.43.1 (08-Jun-2016)
/dev/sdb3 contains a ext2 file system
        last mounted on Sun Jan 22 02:40:04 2017
Proceed anyway? (y,n) y
Creating filesystem with 79167488 4k blocks and 38656 inodes
Filesystem UUID: cd62f259-2a4a-4be8-8d13-a9229e88f119
Superblock backups stored on blocks: 
        32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208, 
        4096000, 7962624, 11239424, 20480000, 23887872, 71663616, 78675968

Allocating group tables: done                            
Writing inode tables: done                            
Writing superblocks and filesystem accounting information: done

Still 38656 inodes @ 8M/inode.

Inode every 48M (ext4)

Code:

root@porteus:/home/guest# time mkfs.ext4 -b 4096 -m0 -i50331648 /dev/sdb3 
mke2fs 1.43.1 (08-Jun-2016)
/dev/sdb3 contains a ext2 file system
        created on Sun Jan 22 16:10:58 2017
Proceed anyway? (y,n) y
Creating filesystem with 79167488 4k blocks and 38656 inodes
Filesystem UUID: 2671309d-1c79-455a-9a6b-b9cfd879eb25
Superblock backups stored on blocks: 
        32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208, 
        4096000, 7962624, 11239424, 20480000, 23887872, 71663616, 78675968

Allocating group tables: done                            
Writing inode tables: done                            
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done     


real    0m20.955s
user    0m0.028s
sys     0m0.457s

No improvement.

MKE2FS Man Page

Quote:

-N number-of-inodes
Overrides the default calculation of the number of inodes that should be reserved for the filesystem (which is based on the number of blocks and the bytes-per-inode ratio). This allows the user to specify the number of desired inodes directly.

Code:

root@porteus:/home/guest# time mkfs.ext2 -b 4096 -m0 -N4096 /dev/sdb3
mke2fs 1.43.1 (08-Jun-2016)
/dev/sdb3 contains a ext4 file system
        last mounted on Sun Jan 22 17:23:19 2017
Proceed anyway? (y,n) y
Creating filesystem with 79167488 4k blocks and 38656 inodes
Filesystem UUID: b48aacde-ee9f-4ed5-ab6c-ad09bfa8aca3
Superblock backups stored on blocks: 
        32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208, 
        4096000, 7962624, 11239424, 20480000, 23887872, 71663616, 78675968

Allocating group tables: done                            
Writing inode tables: done                            
Writing superblocks and filesystem accounting information: done     


real    0m32.970s
user    0m0.029s
sys     0m0.282s

Still 38656 inodes. No override!

By Way of Experiment

Code:

root@porteus:/home/guest# time mkfs.ext2 -b 8192 -m0 -N 4096 /dev/sdb3
Warning: blocksize 8192 not usable on most systems.
mke2fs 1.43.1 (08-Jun-2016)
/dev/sdb3 contains a ext2 file system
        created on Sun Jan 22 21:30:13 2017
Proceed anyway? (y,n) y
mkfs.ext2: 8192-byte blocks too big for system (max 4096)
Proceed anyway? (y,n) y
Warning: 8192-byte blocks too big for system (max 4096), forced to continue
Creating filesystem with 39583744 8k blocks and 19360 inodes
Filesystem UUID: 40711675-e673-4a14-a9cf-66403251f442
Superblock backups stored on blocks: 
        65528, 196584, 327640, 458696, 589752, 1638200, 1769256, 3210872, 
        5307768, 8191000, 15923304, 22476104

Allocating group tables: done                            
Writing inode tables: done                            
Writing superblocks and filesystem accounting information: done   


real    0m35.978s
user    0m0.017s
sys     0m0.127s

Looks like for Block Size of 4096 bytes, max of 8 MiB per inode Ratio is Hardcoded in.

syg00 · 01-22-2017, 06:14 PM

Why ext2 ?. That (native) code is so old there have been serious discussions to remove the support for it altogether.
As for trying to force allocation, have a look at "-T". Probably won't work on ext2, but there is no reason to even consider that IMHO.

There are also other (better ?) filesystems for really large file allocation.

Bogomips_ · 01-23-2017, 07:26 PM

^ There is no point in suggesting -T if one has not tried it themselves. The most that -T does is 6 MiB an inode, or something of that order. Example #4 was done with ext4, and resulted in the same limitations. Ext2 does not have journalling, and for my purposes journalling would be just a superfluous overhead .

syg00 · 01-23-2017, 07:49 PM

You can run ext4 without journalling. Best of both worlds - you get the new code for large allocations, extents etc as well.
-T worked fine when I have used it - but only tried it on ext4. I did say it might not be of assistance on ext2.

Bogomips_ · 01-24-2017, 07:24 PM

Quote:

Originally Posted by syg00

You can run ext4 without journalling. Best of both worlds

Thanks for heads up.

Going with it:

High inode density.

Code:

root@porteus:/home/guest# mkfs.ext4 -b 4096 -m 0 -T huge -O ^has_journal /dev/sdb3 
mke2fs 1.43.1 (08-Jun-2016)
/dev/sdb3 contains a ext2 file system
        created on Sun Jan 22 21:35:29 2017
Proceed anyway? (y,n) y
Creating filesystem with 79167488 4k blocks and 4947968 inodes
Filesystem UUID: eb1bfdd0-78d7-4a82-818a-e3b5589e6718
Superblock backups stored on blocks: 
        32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208, 
        4096000, 7962624, 11239424, 20480000, 23887872, 71663616, 78675968

Allocating group tables: done                            
Writing inode tables: done                            
Writing superblocks and filesystem accounting information: done

root@porteus:/home/guest# tune2fs -l /dev/sdb3 | awk -F: ' \
>     /^Block count:/ { blocks = $2 } \
>     /^Inode count:/ { inodes = $2 } \
>     /^Block size:/ { block_size = $2 } \
>     END { blocks_per_inode = blocks/inodes; \
>           print "blocks per inode:\t", blocks_per_inode, \
>                 "\nbytes per inode:\t", blocks_per_inode * block_size }'
blocks per inode:        16 
bytes per inode:         65536

4 MiBs per Inode

Code:

root@porteus:/home/guest# mkfs.ext4 -b 4096 -m 0 -T largefile4 -O ^has_journal /dev/sdb3 
mke2fs 1.43.1 (08-Jun-2016)
/dev/sdb3 contains a ext4 file system
        created on Tue Jan 24 16:26:10 2017
Proceed anyway? (y,n) y
Creating filesystem with 79167488 4k blocks and 77312 inodes
Filesystem UUID: 7ff6af42-a63f-4e57-a282-38e80a2b9879
Superblock backups stored on blocks: 
        32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208, 
        4096000, 7962624, 11239424, 20480000, 23887872, 71663616, 78675968

Allocating group tables: done                            
Writing inode tables: done                            
Writing superblocks and filesystem accounting information: done     

root@porteus:/home/guest# tune2fs -l /dev/sdb3 | awk -F: ' \
    /^Block count:/ { blocks = $2 } \
    /^Inode count:/ { inodes = $2 } \
    /^Block size:/ { block_size = $2 } \
    END { blocks_per_inode = blocks/inodes; \
          print "blocks per inode:\t", blocks_per_inode, \
                "\nbytes per inode:\t", blocks_per_inode * block_size }'
blocks per inode:        1024 
bytes per inode:         4194304

38656 Inodes

-T -i Specified

Code:

root@porteus:/home/guest# mkfs.ext4 -b 4096 -m 0 -T largefile4 -O ^has_journal -i 67108864  /dev/sdb3
mke2fs 1.43.1 (08-Jun-2016)
/dev/sdb3 contains a ext4 file system
        created on Tue Jan 24 16:35:06 2017
Proceed anyway? (y,n) y
Creating filesystem with 79167488 4k blocks and 38656 inodes
Filesystem UUID: 2b178c74-264f-4f65-b183-61860ca77492
Superblock backups stored on blocks: 
        32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208, 
        4096000, 7962624, 11239424, 20480000, 23887872, 71663616, 78675968

Allocating group tables: done                            
Writing inode tables: done                            
Writing superblocks and filesystem accounting information: done

-T -i -N Specified

Code:

root@porteus:/home/guest# mkfs.ext4 -b 4096 -m 0 -T largefile4 -O ^has_journal -i 67108864  /dev/sdb3
mke2fs 1.43.1 (08-Jun-2016)
/dev/sdb3 contains a ext4 file system
        created on Tue Jan 24 16:35:06 2017
Proceed anyway? (y,n) y
Creating filesystem with 79167488 4k blocks and 38656 inodes
Filesystem UUID: 2b178c74-264f-4f65-b183-61860ca77492
Superblock backups stored on blocks: 
        32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208, 
        4096000, 7962624, 11239424, 20480000, 23887872, 71663616, 78675968

Allocating group tables: done                            
Writing inode tables: done                            
Writing superblocks and filesystem accounting information: done

Just -N Specified. Again 38656 Inodes.

Code:

root@porteus:/home/guest# time mkfs.ext4 -b 4096 -m 0 -N 4096 -O ^has_journal  /dev/sdb3mke2fs 1.43.1 (08-Jun-2016)
/dev/sdb3 contains a ext4 file system
        created on Tue Jan 24 17:17:04 2017
Proceed anyway? (y,n) y
Creating filesystem with 79167488 4k blocks and 38656 inodes
Filesystem UUID: d5038994-c3be-4403-9750-4d874a944ef2
Superblock backups stored on blocks: 
        32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208, 
        4096000, 7962624, 11239424, 20480000, 23887872, 71663616, 78675968

Allocating group tables: done                            
Writing inode tables: done                            
Writing superblocks and filesystem accounting information: done     


real    0m11.345s
user    0m0.026s
sys     0m0.188s


root@porteus:/home/guest# tune2fs -l /dev/sdb3 | awk -F: ' \
    /^Block count:/ { blocks = $2 } \
    /^Inode count:/ { inodes = $2 } \
    /^Block size:/ { block_size = $2 } \
    END { blocks_per_inode = blocks/inodes; \
          print "blocks per inode:\t", blocks_per_inode, \
                "\nbytes per inode:\t", blocks_per_inode * block_size }'
blocks per inode:        2048 
bytes per inode:         8388608

Inode Ratio of 8 MiB to the Inode

Looks like will have to report this as a deficiency, which is a bore, but they are apparently short of resources for testing.