Andrejs life with ORACLE, knowledge base: October 2010

Friday, October 29, 2010

HOW TO MANAGE ASYNCH I/O on RHEL

REASON

1. You can get significant performance in I/O operations on DB

To verify ASYNCH

To verify whether the oracle executable ($ORACLE_HOME/bin/oracle) was linked with asynchronous I/O, run

In the following example, oracle is linked with asynchronous I/O, otherwise you get nothing.

ldd $ORACLE_HOME/bin/oracle | grep libaio

libaio.so.1 => /usr/lib64/libaio.so.1 (0x0000002a96ef7000)

nm $ORACLE_HOME/bin/oracle | grep io_getevent

w io_getevents@@LIBAIO_0.4

Link ASYNCH to oracle, if it is not linked

shutdown all

cd $ORACLE_HOME/rdbms/lib

make -f ins_rdbms.mk async_on

make -f ins_rdbms.mk ioracle

startup

Even if oracle is linked it doesn’t mean your ASYNCH is ON.

Change parameter in case of block device like RAW

# init.ora

disk_asynch_io = true

#spfile

alter system set disk_asynch_io = true scope=spfile;

and if you have file system like ext3 than add this one also

# init.ora

filesystemio_options = asynch

#spfile

alter system set filesystemio_options='ASYNCH' scope=both;

Check your job

ASYNCH is ON

cat /proc/slabinfo | grep kio

kioctx 305 360 384 10 1 : tunables 54 27 8 : slabdata 36 36 0

kiocb 255 255 256 15 1 : tunables 120 60 8 : slabdata 17 17 0

Uninstall, Fall back

shutdown all

cd $ORACLE_HOME/rdbms/lib

make -f ins_rdbms.mk async_off

make -f ins_rdbms.mk ioracle

startup

ASYNCH is OFF

cat /proc/slabinfo | grep kio

kioctx 121 140 384 10 1 : tunables 54 27 8 : slabdata 14 14 0

kiocb 0 0 256 15 1 : tunables 120 60 8 : slabdata 0 0 0

Tuesday, October 26, 2010

How to enable and disable RAC option in version 9.2.0.1 to 11.1.0.8

REASON

1. Sometimes for ORACLE RAC DB you need to check backup/restore on server with not linked RAC option

2. Restore DB to new server where RAC option is not enabled and you can get

ORA-00439: feature not enabled: Real Application Clusters

3. If you try DBCA with no RAC servers and cluster manager with a linked RAC option into oracle you can get

ORA-00603: ORACLE server session terminated by fatal error

ORA-27504: IPC error creating OSD context

ORA-27300: OS system dependent operation:if_not_found failed with status: 0

ORA-27301: OS failure message: Error 0

ORA-27302: failure occurred at: skgxpvaddr9

CHECK IF RAC_ON or RAC_OFF

cd $ORACLE_HOME/rdbms/lib

nm -r libknlopt.a | grep -c kcsm.o

If above command returns 0, then RAC is not linked. If it returns >= 1, then it is linked.

#spfile

alter system set cluster_database=false scope=spfile;

ENABLE RAC OPTION

cd $ORACLE_HOME/rdbms/lib

shutdown everything

make -f ins_rdbms.mk rac_on ioracle

DISABLE RAC OPTION

cd $ORACLE_HOME/rdbms/lib

shutdown everything

make -f ins_rdbms.mk rac_off ioracle

Friday, October 22, 2010

How fast you are in unziping on Linux

REASON
you might need to unpack many files in directory on Linux

Try sequential unzip

for i in `ls -1 | grep .zip$`; do unzip $i; done
or

ls -1 *.zip | xargs -n 1 unzip &

Parallel unzipping , be careful it may hang your host for a while

for i in `ls -1 | grep .zip$`; do unzip $i & done

Try gunzip tar

for i in `ls -1 | grep .zip$`; do tar xfvz $i; done

IOUG EMEA Presidents meeting, Brussels, 2010-10

IOUG EMEA Presidents meeting, Brussels, 2010-10 - a set on Flickr

Thursday, October 21, 2010

How to check if PSU is applied successfully

opatch apply

cd $ORACLE_HOME/rdbms/admin

sysdba

startup

@catbundle.sql psu apply

exit

before 11.2.0.2

less $ORACLE_HOME/cfgtoollogs/catbundle/`ls -1t $ORACLE_HOME/cfgtoollogs/catbundle | head -n 1 | awk '{print $1}'`|grep -i error

>= 11.2.0.2

less $ORACLE_HOME/cfgtoollogs/opatch/`ls -1t $ORACLE_HOME/cfgtoollogs/opatch/ | head -n 1 | awk '{print $1}'`|grep -i error

Tuesday, October 19, 2010

Summit at Oracle Headquarters! 24-26 January 2011

Oracle will host the International Oracle Users Group Leaders Community Summit at Oracle Headquarters, Redwood Shores California January 24-26, 2011.

This is the Summit for users group leaders to network, share best practices, learn about Oracle campaigns and discuss issues that are important to OUG members.