We cannot force the writes to a specific disk. At least I am not aware of any such thing.
Oracle will write the primary-copy to any disk in a normal redundancy environment.
The default behavior is to read from the primary-copy, which can be alterted by the parameter that you have mentioned.
If we assume that all the data is written simultaneously to one disk, there are chances of performance degradation as the same disk controller will be active at one time to do I/Os.

- Saurabh Sood

ASM_PREFERRED_READ_FAILURE_GROUPS is mainly used for RAC instances and that too stretch clusters i.e when RAC nodes are not sitting in same cluster. On single instance it doesn’t make any sense. Refer to oracle doc to read more about this

http://docs.oracle.com/cd/E11882_01/rac.112/e16795/storage.htm#RACAD820

Cheers
Amit

please guide me!

My manager asked me to configure ASM in 11g with single instance database!
with Normal redundancy with two disks as one disgroup(mirror)
he asked me two copies of data wil be there in two disks respectively…
he wants to write data to one disk and read data from one disk and he suggested me that…. using preferred Mirror Read 11g we can achieve this!

guide me…is there any document for this….

please ……..

Fastest way of migrating ASM storage would be to create new volumes of same size on new storage. Shutdown the databases and ASM instance and replicate the old disks to new disks. Make the new disks available on server (remove the reference of old one) and ensure the disk permissions are correct. Then simply start ASM instance and mount diskgroup.

Cheers
Amit

I’m looking for a Procedure how to migrate ASM (RAW-Devices) from an old SAN-Storage to a new one.
We have 2 Nodes Rac (11gr1) deployed on sun solaris sparc 64 with two hba cards, and 5 databases on each node including +ASM1 and +ASM2 instances.
To get near Informations:

$ kfod disks=all
——————————————————————————–
Disk Size Path User Group
================================================================================
1: 102394 Mb /dev/rdsk/emcpower10b oracle dba
2: 102394 Mb /dev/rdsk/emcpower11b oracle dba
3: 499 Mb /dev/rdsk/emcpower1b oracle oinstall
4: 6143 Mb /dev/rdsk/emcpower2b oracle dba
5: 102394 Mb /dev/rdsk/emcpower3b oracle dba
6: 102394 Mb /dev/rdsk/emcpower4b oracle dba
7: 102394 Mb /dev/rdsk/emcpower5b oracle dba
8: 6143 Mb /dev/rdsk/emcpower7b oracle dba
9: 61436 Mb /dev/rdsk/emcpower8b oracle dba
10: 102394 Mb /dev/rdsk/emcpower9b oracle dba
——————————————————————————–
ORACLE_SID ORACLE_HOME
================================================================================
+ASM2 /opt/oracle/product/11gr1/db_1
+ASM1 /opt/oracle/product/11gr1/db_1

$ kfod asm_diskstring=discoverystring
——————————————————————————–
ORACLE_SID ORACLE_HOME
================================================================================
+ASM2 /opt/oracle/product/11gr1/db_1
+ASM1 /opt/oracle/product/11gr1/db_1

$ crs_stat -t
Name Typ Ziel Status Host
————————————————————
ora….11.inst application ONLINE ONLINE lbd-db1
ora….12.inst application ONLINE ONLINE lbd-db2
ora.LBD01.db application ONLINE ONLINE lbd-db2
ora….21.inst application ONLINE ONLINE lbd-db1
ora….22.inst application ONLINE ONLINE lbd-db2
ora.LBD02.db application ONLINE ONLINE lbd-db1
ora….31.inst application ONLINE ONLINE lbd-db1
ora….32.inst application ONLINE ONLINE lbd-db2
ora.LBD03.db application ONLINE ONLINE lbd-db2
ora….01.inst application ONLINE ONLINE lbd-db1
ora….02.inst application ONLINE ONLINE lbd-db2
ora.LBD10.db application ONLINE ONLINE lbd-db2
ora….SM1.asm application ONLINE ONLINE lbd-db1
ora….B1.lsnr application ONLINE ONLINE lbd-db1
ora….db1.gsd application ONLINE ONLINE lbd-db1
ora….db1.ons application ONLINE ONLINE lbd-db1
ora….db1.vip application ONLINE ONLINE lbd-db1
ora….SM2.asm application ONLINE ONLINE lbd-db2
ora….B2.lsnr application ONLINE ONLINE lbd-db2
ora….db2.gsd application ONLINE ONLINE lbd-db2
ora….db2.ons application ONLINE ONLINE lbd-db2
ora….db2.vip application ONLINE ONLINE lbd-db2

SYS@+ASM1 > select GROUP_NUMBER, DISK_NUMBER, NAME, TOTAL_MB, PATH, FAILGROUP from v$asm_disk order by 1,2,3,4,5;
GROUP DISK NAME TOTAL_MB PATH FAILGROUP
———- ———- ————— ———- —————————— ————
0 7 0 /dev/rdsk/emcpower1b
1 0 DATA_0000 102394 /dev/rdsk/emcpower10b DATA_0000
1 1 DATA_0001 102394 /dev/rdsk/emcpower11b DATA_0001
1 2 DATA_0002 102394 /dev/rdsk/emcpower3b DATA_0002
1 3 DATA_0003 102394 /dev/rdsk/emcpower4b DATA_0003
1 4 DATA_0004 102394 /dev/rdsk/emcpower5b DATA_0004
1 5 DATA_0005 102394 /dev/rdsk/emcpower9b DATA_0005
2 0 LOG1_0000 6143 /dev/rdsk/emcpower2b LOG1_0000
3 0 LOG2_0000 6143 /dev/rdsk/emcpower7b LOG2_0000
4 0 RECOVLBD_0000 61436 /dev/rdsk/emcpower8b RECOVLBD_0000

Have you got any idea to do that, or could you give me a link to get Infos about the case.

Thanks and regards
Niroobakhsh
from Germany

I haven’t used udev to configure device persistence. You can refer to following oracle whitepaper on same

http://www.oracle.com/technology/products/database/asm/pdf/device-mapper-udev-crs-asm%20rh4.pdf

I think using ASMLIB is much simpler option. Any specific reasons , you are not using same.

Cheers
Amit

I have problem with asmdisk detection after reboot.

This is started after putting the udev rule to set disk timeout to 60 sec.

Udev rule:
BUS=”scsi”, PROGRAM=”/sbin/scsi_timeout.sh”
Script content:
#!/bin/sh
for i in /sys/block/sd*/device;do
echo 60 > $i/timeout
done
============
OS: RHEL 4, 2.6.9-55.0.6.ELsmp
=============
Oracle version: 10.2
===========

If we remove the rule and reboot the server it is working fine.
Any idea?

alter diskgroup resize disk size G rebalance ;

If you do not specify power during command, it takes value of asm_power_limit initialization parameter.

Can find also detail in SQL reference book
http://download.oracle.com/docs/cd/B19306_01/server.102/b14200/statements_1006.htm#i2168828

i have allocated all the size in my san disk to create a single diskgroup in asm ,But i have 80% of the space as unused , how can i shrink it

As you said that the ASM instance is mounted and running, i think this is the cause of the problem.

In DataBase versions earlier than 10.1.0.5 this issue can come because of the fact that the ASM diskgroups are already mounted.

If you are at some earlier version than 10.1.0.5 than try to upgrade to 10.1.0.5 (PatchSet) and again redo the process.

Cheers !!

Did you check Metalink Note:332046.1

If above note does not work, then can you give output of following

SQL> select INST_ID,GROUP_NUMBER,NAME,STATE from GV$ASM_DISKGROUP;

Also check Alert.log for any other errors

Cheers
Amit

The asm instance is up and running, the name of the diskgroup is selected from the alternative presented by dbca

Any ideas?
Thanks a lot
Roberto

Clusterware is not required for ASM to work in a Single Instance Database. When you install ASM, you would be required to run “localconfig add” on Unix systems. This will create a service called Cluster Syncronization Service (CSS) which will take care of ASM instance. There is no need for CRS,EVMD and OPROCD.

Hope this clears your doubt. Else let me know!

Cheers
Amit