Determine database read/write statistics

Question

From the following (in Oracle documentation)
DB_WRITER_PROCESSES parameter is useful for systems that modify data heavily. It specifies the initial number of database writer processes for an instance.
And from the "Deployment Guide for Oracle on Windows using Dell PowerEdge Servers.pdf" in http://www.oracle.com/technology/tech/windows/index.html
RAID LEVELS I have heard that it is for disks where datafiles reside the following is true
If I/O is <= 90% reads, then it is advisable to go for RAID 10. If I/O is > 90% reads, then RAID 5 could be considered.
I would like to know
1. How do we find out whether our database is "read heavy" or "write heavy"? Are there are scripts available please?
2. In commercial environments, what sort of RAID Levels are normally used for "read heavy and write heavy databases?
Edited by: sandeshd on Oct 14, 2009 3:11 PM

Answer 1

We were in a similar situation some weeks ago, we decided to make a trigger (logout) for saving the butes for a specific schema, you can work with this data importing it with Excel or something similar.
DROP TABLESPACE BYTES_USUARIOS INCLUDING CONTENTS AND DATAFILES;
CREATE TABLESPACE BYTES_USUARIOS DATAFILE
'/oradata/oradata/ewok/bytes_usuarios.dbf' SIZE 1024M AUTOEXTEND ON NEXT 25M MAXSIZE UNLIMITED
LOGGING
ONLINE
PERMANENT
EXTENT MANAGEMENT LOCAL AUTOALLOCATE
BLOCKSIZE 8K
SEGMENT SPACE MANAGEMENT MANUAL
FLASHBACK ON;
+++++++++++
CREATE USER B1
IDENTIFIED BY VALUES %password%
DEFAULT TABLESPACE BYTES_USUARIOS
TEMPORARY TABLESPACE TEMP
PROFILE MONITORING_PROFILE
ACCOUNT UNLOCK;
-- 1 Role for B1
GRANT CONNECT TO B1;
ALTER USER B1 DEFAULT ROLE NONE;
-- 2 System Privileges for B1
GRANT CREATE TABLE TO B1;
GRANT CREATE SESSION TO B1;
-- 1 Tablespace Quota for B1
ALTER USER B1 QUOTA UNLIMITED ON BYTES_USUARIOS;
++++++++++
CREATE TABLE b1.BYTES_USUARIOS
USERNAME VARCHAR2(30 BYTE),
SID NUMBER,
SERIAL# NUMBER,
MACHINE VARCHAR2(64 BYTE),
LOGON_TIME DATE,
CLS VARCHAR2(53 BYTE),
NAME VARCHAR2(64 BYTE),
VALUE NUMBER
TABLESPACE BYTES_USUARIOS
PCTUSED 40
PCTFREE 10
INITRANS 1
MAXTRANS 255
STORAGE (
INITIAL 64K
MINEXTENTS 1
MAXEXTENTS 2147483645
PCTINCREASE 0
FREELISTS 1
FREELIST GROUPS 1
BUFFER_POOL DEFAULT
LOGGING
NOCOMPRESS
NOCACHE
NOPARALLEL
MONITORING;
grant all on b1.bytes_usuarios to system;
++++++++++++++++
grant select on v_$mystat to system;
grant select on v_$session to system;
grant select on v_$statname to system;
DROP TRIGGER SYSTEM.TRG_LOGOFF;
CREATE OR REPLACE TRIGGER SYSTEM.TRG_LOGOFF
BEFORE LOGOFF
ON DATABASE
DECLARE
--VAR_CADENA VARCHAR(20);
begin
--VAR_CADENA := "%bytes%";
--execute immediate '       
insert into b1.bytes_usuarios (
select
ss.username,
ss.sid, ss.serial#, ss.machine, ss.logon_time,
decode (bitand( 1,class), 1,'User ', '') ||
decode (bitand( 2,class), 2,'Redo ', '') ||
decode (bitand( 4,class), 4,'Enqueue ', '') ||
decode (bitand( 8,class), 8,'Cache ', '') ||
decode (bitand( 16,class), 16,'Parallel Server ', '') ||
decode (bitand( 32,class), 32,'OS ', '') ||
decode (bitand( 64,class), 64,'SQL ', '') ||
decode (bitand(128,class),128,'Debug ', '') cls,
name,(value/1024/1024) from sys.v_$statname m, sys.v_$mystat s, sys.v_$session ss
where
m.statistic# = s.statistic#
and (name like '%bytes sent%' or name like '%bytes received%')
and ss.sid = (select distinct sid from sys.v_$mystat)
end;
++++++++++++
TODO
select username, name, sum(value)
from b1.bytes_usuarios
group by username, name
order by username, name
SOLO bytes enviados
select username, name, sum(value)
from b1.bytes_usuarios
where
and name like '%sent%'
group by username, name
order by username, name
SOLO bytes recibidos
select username, name, sum(value)
from b1.bytes_usuarios
where
and name like '%received%'
group by username, name
order by username, name