Why does Oracle Database created the redo logs with a blocksize of 512 k when the flesystems have a

Hi experts:
Why does Oracle Database 11.2 created the redo logs with a blocksize of 512 k when the flesystems have a blocksize of 4096?

-oracle:/home/oracle> lsfs -q /dev/oemlv_red1
Name            Nodename   Mount Pt               VFS   Size    Options    Auto Accounting
/dev/oemlv_red1 --         /claroproem/REDO1      jfs2  6291456 rw         yes  no
  (lv size: 6291456, fs size: 6291456, block size: 4096, sparse files: yes, inline log: no, inline log size: 0, EAformat: v1, Quota: no, DMAPI: no, VIX: yes, EFS: no, ISNAPSHOT: no, MAXEXT: 0)
-oracle:/home/oracle> exit



SQL> SELECT BLOCKSIZE FROM V$LOG;

 BLOCKSIZE
----------
       512
       512
       512