Redo Log Block Size on IBM: Linux on System z
(Doc ID 1605309.1)
Last updated on FEBRUARY 17, 2019
Applies to:Oracle Database - Enterprise Edition - Version 18.104.22.168 and later
Oracle Database Cloud Schema Service - Version N/A and later
Oracle Database Exadata Express Cloud Service - Version N/A and later
Oracle Database Exadata Cloud Machine - Version N/A and later
Oracle Cloud Infrastructure - Database Service - Version N/A and later
IBM: Linux on System z
To create redo logs with a block size of 512 on block devices with a 512byte sector size on the IBM: Linux on System z platform to avoid wasting redo log space.
A block device "/dev/sda1" which has an ext3 filesystem with a default blocksize of 4K have redo log files with a default block size of 4k despite having a sector size of 512bytes.
The sector size is 512:-
# blockdev --getpbsz /dev/sda1
When adding redo logs they are created with a default block size of 4K:-
SQL>select blocksize from v$log
When attempting to override the default blocksize e.g. as per http://docs.oracle.com/cd/E18283_01/server.112/e17120/onlineredo002.htm#CHDFBDJC
SQL> alter database add logfile group 10 '/oracle/redo/redo10-tmp.log' size 10m blocksize 512 reuse;
alter database add logfile group 10 '/oracle//redo/redo10-tmp.log' size 10m blocksize 512 reuse
ERROR at line 1:
ORA-01377: Invalid log file block size
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