Determining the block size in oracle

select value from v$parameter where name = 'db_block_size'
SQL> show parameter block_size
Getting the block size for Red Hat

#tune2fs -l /dev/vgxx/lvolx   ( this does not work for xfs, use xfs_info <par> ) 
 
Sample output below:
 
# tune2fs -l /dev/emcpowera1
tune2fs 1.39 (29-May-2006)
Filesystem volume name:   <none>
Last mounted on:          <not available>
Filesystem UUID:          93c46938-317f-48d9-af94-1339b53c9fcb
Filesystem magic number:  0xEF53
Filesystem revision #:    1 (dynamic)
Filesystem features:      has_journal resize_inode dir_index filetype needs_recovery sparse_super large_file
Default mount options:    (none)
Filesystem state:         clean
Errors behavior:          Continue
Filesystem OS type:       Linux
Inode count:              15728640
Block count:              31457270
Reserved block count:     1572863
Free blocks:              30915647
Free inodes:              15728629
First block:              0
Block size:               4096
Fragment size:            4096
Reserved GDT blocks:      1016
Blocks per group:         32768
Fragments per group:      32768
Inodes per group:         16384
Inode blocks per group:   512
Filesystem created:       Tue Mar 23 23:28:18 2010
Last mount time:          Tue Mar 23 23:29:06 2010
Last write time:          Tue Mar 23 23:29:06 2010
Mount count:              1
Maximum mount count:      31
Last checked:             Tue Mar 23 23:28:18 2010
Check interval:           15552000 (6 months)
Next check after:         Sun Sep 19 23:28:18 2010
Reserved blocks uid:      0 (user root)
Reserved blocks gid:      0 (group root)
First inode:              11
Inode size:               128
Journal inode:            8
Default directory hash:   tea
Directory Hash Seed:      aa2c3208-4edf-4dee-b978-ab6c9a1e88fc
Journal backup:           inode blocks

Also:
/sbin/dumpe2fs /dev/hda2 | grep 'Block size'