[linux-lvm] Problem mounting ext2 fs on LVM

[Urs Thuermann]

After having decided that the performance problem I described in the
other thread in this ML are probably not that important for me, I
tried to create an ext2 fs with 1024 byte blocks on a 1 GB LV.

But I can't mount it after creating the fs.  I can mount it if I
create it on sda5 instead of the LV, or if I chosse 4K block size.  I
start with no VGs defined.

1K block size on /dev/sda5 is ok:

    isnogud:/root# fdisk -l /dev/sda|grep sda5
    /dev/sda5            80       399   2570368+  8e  Linux LVM
    isnogud:/root# mke2fs -b 1024 /dev/sda5 1048576
    mke2fs 1.19, 13-Jul-2000 for EXT2 FS 0.5b, 95/08/09
    Filesystem label=
    OS type: Linux
    Block size=1024 (log=0)
    Fragment size=1024 (log=0)
    131072 inodes, 1048576 blocks
    52428 blocks (5.00%) reserved for the super user
    First data block=1
    128 block groups
    8192 blocks per group, 8192 fragments per group
    1024 inodes per group
    Superblock backups stored on blocks: 
    	    8193, 24577, 40961, 57345, 73729, 204801, 221185, 401409, 663553, 
    	    1024001
    
    Writing inode tables: done                            
    Writing superblocks and filesystem accounting information: done
    isnogud:/root# mount /dev/sda5 /mnt
    isnogud:/root# df /mnt
    Filesystem           1k-blocks      Used Available Use% Mounted on
    /dev/sda5              1031880        13    979439   0% /mnt
    isnogud:/root# umount /mnt

But if I try the same on an LV, I get

    isnogud:/root# pvcreate /dev/sda5
    pvcreate -- physical volume "/dev/sda5" successfully created
    
    isnogud:/root# vgcreate vg0 /dev/sda5
    vgcreate -- INFO: using default physical extent size 4 MB
    vgcreate -- INFO: maximum logical volume size is 255.99 Gigabyte
    vgcreate -- doing automatic backup of volume group "vg0"
    vgcreate -- volume group "vg0" successfully created and activated
    
    isnogud:/root# lvcreate -n test /dev/vg0 -L 1024
    lvcreate -- doing automatic backup of "vg0"
    lvcreate -- logical volume "/dev/vg0/test" successfully created
    
    isnogud:/root# mke2fs -b 1024 /dev/vg0/test
    mke2fs 1.19, 13-Jul-2000 for EXT2 FS 0.5b, 95/08/09
    Filesystem label=
    OS type: Linux
    Block size=1024 (log=0)
    Fragment size=1024 (log=0)
    131072 inodes, 1048576 blocks
    52428 blocks (5.00%) reserved for the super user
    First data block=1
    128 block groups
    8192 blocks per group, 8192 fragments per group
    1024 inodes per group
    Superblock backups stored on blocks: 
    	    8193, 24577, 40961, 57345, 73729, 204801, 221185, 401409, 663553, 
    	    1024001
    
    Writing inode tables: done                            
    Writing superblocks and filesystem accounting information: done
    isnogud:/root# mount /dev/vg0/test /mnt
    mount: wrong fs type, bad option, bad superblock on /dev/vg0/test,
    	   or too many mounted file systems

Any idea, what's wrong here?   I works, when I choose 4K block size:

    isnogud:/root# mke2fs -b 4096 /dev/vg0/test
    mke2fs 1.19, 13-Jul-2000 for EXT2 FS 0.5b, 95/08/09
    Filesystem label=
    OS type: Linux
    Block size=4096 (log=2)
    Fragment size=4096 (log=2)
    131072 inodes, 262144 blocks
    13107 blocks (5.00%) reserved for the super user
    First data block=0
    8 block groups
    32768 blocks per group, 32768 fragments per group
    16384 inodes per group
    Superblock backups stored on blocks: 
    	    32768, 98304, 163840, 229376
    
    Writing inode tables: done                            
    Writing superblocks and filesystem accounting information: done
    isnogud:/root# mount /dev/vg0/test /mnt
    isnogud:/root# df /mnt
    Filesystem           1k-blocks      Used Available Use% Mounted on
    /dev/vg0/test          1032088        20    979640   0% /mnt
    isnogud:/root# umount /mnt


urs