Creating asm diskgroup

hi,
i am running oracle 10.2.0.1.0 on win 2003 and i configured ASM. (Testing ENV).
i have four drive without any file system i.e D,E,F,G each having 10gb.
i created one diskgroup i.e grp1 with normal redundancy, that use D,E drive through DBCA.
now i want to create another diskgroup i.e grp2 through COMMAND line.
I am running this
create diskgroup grp2 normal redundancy
failgroup fail1 disk '\devices\harddisk0\partition5' ----- (F)
failgroup fail2 disk '\devices\harddisk0\partition6' ----- (G)
but i am getting error
create diskgroup mydrp2 normal redundancy
ERROR at line 1:
ORA-15018: diskgroup cannot be created
ORA-15031: disk specification '\devices\harddisk0\partition6' matches no disks
ORA-15056: additional error message
OSD-04659: Message 4659 not found; product=RDBMS; facility=SOSD
O/S-Error: (OS 3) The system cannot find the path specified.
ORA-15031: disk specification '\devices\harddisk0\partition5' matches no disks
ORA-15056: additional error message
OSD-04659: Message 4659 not found; product=RDBMS; facility=SOSD
O/S-Error: (OS 3) The system cannot find the path specified.
please help
Edited by: Hare krishna on Mar 3, 2011 5:06 AM

Hi,
Does the disk appear under v$asm_disk?
You can check it as:
select group_number, name, path from v$asm_disk;
Check the path is currect and try with the command it should work.
I also suggest you to read the below link for useful info:
http://www.oracle-base.com/articles/10g/AutomaticStorageManagement10g.php
Best regards,
Rafi.
http://rafioracledba.blogspot.com/
Edited by: Rafi (Oracle DBA) on Mar 3, 2011 5:27 AM

Similar Messages

Unable to Create ASM Diskgroup ORA-15020 and ORA-15018

Hello Team,
Unable to create ASM diskgroup with following error:
SQL> create diskgroup data_asm1 external redundancy disk '/dev/sdf*';
create diskgroup data_asm1 external redundancy disk '/dev/sdf*'
ERROR at line 1:
ORA-15018: diskgroup cannot be created
ORA-15020: discovered duplicate ASM disk "DATA_ASM1_0000"
ASM Diskstring
SQL> show parameter asm_diskstring
NAME                                 TYPE        VALUE
asm_diskstring                       string      /dev/oracleasm/disks/DISK*, /dev/sd*
Please let me know how to i solve this issue
Regards,

Hi Tobi,
I checked the status of the res GRID.dg ... it was offline on second node. Logged on second node and checked the status of it viz:v$asm_diskgroup, it was dismount. I mounted it and then try to add the newly added diskgroup(+GRID) with OCR and viola it worked....
========================================================
ora.GRID.dg
               ONLINE ONLINE       rac3
               OFFLINE OFFLINE      rac4
SQL> select group_number,name,state,type from v$asm_diskgroup;
GROUP_NUMBER NAME                           STATE       TYPE
           1 DATA                           MOUNTED     EXTERN
           0 GRID                           DISMOUNTED
SQL> alter diskgroup grid mount;
Diskgroup altered.
SQL> select group_number,name,state,type from v$asm_diskgroup;
GROUP_NUMBER NAME                           STATE       TYPE
           1 DATA                           MOUNTED     EXTERN
           2 GRID                           MOUNTED     EXTERN
==============================================
ora.GRID.dg
               ONLINE ONLINE       rac3
               ONLINE ONLINE       rac4
===============================================
[root@rac3 bin]# ./ocrcheck
Status of Oracle Cluster Registry is as follows :
         Version                  :          3
         Total space (kbytes)     :     262120
         Used space (kbytes)      :       2804
         Available space (kbytes) :     259316
         ID                       :   48011651
         Device/File Name         :      +DATA
                                    Device/File integrity check succeeded
         Device/File Name         :      +grid
                                    Device/File integrity check succeeded
                                    Device/File not configured
                                    Device/File not configured
                                    Device/File not configured
         Cluster registry integrity check succeeded
         Logical corruption check succeeded
==========================================================================================
ASMCMD> lsdg
State    Type    Rebal Sector Block       AU Total_MB Free_MB Req_mir_free_MB Usable_file_MB Offline_disks Voting_files Name
MOUNTED EXTERN N         512   4096 1048576     20472    16263                0           16263              0             N DATA/
MOUNTED EXTERN N         512   4096 1048576      5114     4751                0            4751              0             N GRID/
======================================================================================================
Thank you very much, appreciated..
Thank you Aritra .
Guys you rock.
Regards,

Error in Creating ASM Diskgroups

Hi,
I am trying to create ASM instance and diskgroups on windows XP.
but when i execute "Create diskgroup" command it gives me following error.
SQL> create diskgroup test_asm normal redundancy
2 failgroup controller1 disk 'F:\asmdisks\disk1','F:\asmdisks\disk2'
3 failgroup controlled2 disk 'F:\asmdisks\disk3','F:\asmdisks\disk4';
create diskgroup test_asm normal redundancy
ERROR at line 1:
ORA-15018: diskgroup cannot be created
ORA-15031: disk specification 'F:\asmdisks\disk4' matches no disks
ORA-15025: could not open disk 'F:\ASMDISKS\DISK4'
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OSD-04018: Unable to access the specified directory or device.
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ORA-15059: invalid device type for ASM disk
OSD-04018: Unable to access the specified directory or device.
O/S-Error: (OS 1200) The specified device name is invalid.
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ORA-15025: could not open disk 'F:\ASMDISKS\DISK2'
ORA-15059: invalid device type for ASM disk
OSD-04018: Unable to access the specified directory or device.
O/S-Error: (OS 1200) The specified device name is invalid.
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ORA-15059: inv
The Create command and the init.ora parameter is as follows :
SQL> create diskgroup test_asm normal redundancy
2 failgroup controller1 disk 'F:\asmdisks\disk1','F:\asmdisks\disk2'
3 failgroup controlled2 disk 'F:\asmdisks\disk3','F:\asmdisks\disk4';
# Copyright (c) 1991, 2001, 2002 by Oracle Corporation
# Diagnostics and Statistics
background_dump_dest=E:\oracle\product\10.2.0\db_1\admin\+ASM\bdump
core_dump_dest=E:\oracle\product\10.2.0\db_1\admin\+ASM\cdump
user_dump_dest=E:\oracle\product\10.2.0\db_1\admin\+ASM\udump
# Miscellaneous
instance_type=asm
# Pools
large_pool_size=12M
# Security and Auditing
remote_login_passwordfile=SHARED
asm_diskstring = 'F:\asmdisks\'
SQL> show parameter asm
NAME TYPE VALUE
----------- asm_diskgroups string
asm_diskstring string F:\asmdisks\
asm_power_limit integer 1
SQL> select * from v$asm_disk;
no rows selected

Hi,
is that specified disks (disk 1 to 4) are available in the path 'F:\asmdisks\ ' ???
If ' yes' then what kind of DISK is that ?
And add space between DISK1 F:\asmdisks\ (F:\asmdisks\ DISK) and try.
Thanks,
Ranjith
Edited by: Ranjith on Mar 8, 2012 11:16 PM

Trying to create ASM instance, thinks one already exists?

I've got a problem with creating the ASM instance. Basically, I've reinstalled (v11.1.0.6) clusterware, and two database software installs (one for asm, one for db) due to a san swap. Now, I believe that there is still a hangover to the original installation. When creating the ASM instance through DBCA on Windows, I get the following:
DBCA could not startup the ASM instance configured on this node. To proceed with ASM diskgroup management you need the ASM instance to be up and running. Do you want to recreate the ASM instance on this node?
Yes
Enter password
DBCA will now create and start the ASM instance. After the ASM instance is started, you can create disk groups to be used as storage for your database.
OK
ASM Instance Creation...
Encountered file error when copying listeners from home=D:\oracle\product\11.1.0\asm_2
OK
The operation will be stopped. Re-run DBCA after successfully running NetCA.
I have a listener running (listener_rac), I have a similar problem with netca as it says I already have a listener called listener, which I do not, however, I have created listener_rac instead.
I feel trhat the problem is that ASM1 (for node 1) or ASM2 (for node 2) already exists. However, I can not find either of these. I can create an ASM instance in single node mode, however, this creates an instance +ASM, which does not conflict.
How do I find the non-existent instance, and remove it? (not in registry or services)
Alternatively, any other ideas as to what is happening?
Thank you for your time.

I have a listener running (listener_rac), I have a similar problem with netca as it says I already have a listener called listener, which I do not, however, I have created listener_rac insteadDBCA created your listener... you can check on listener status
srvctl status nodeapps -n node01
Listener is running on node: node01
srvctl status nodeapps -n node02
Listener is running on node: node02
if not start, start it by
Usage: srvctl start listener -n <node_name> [-l <lsnr_name_list>]
srvctl start listener -n node01
by the way, you cam use "netca" delete/recreate (listener_rac)
After that, point to ASM:
I feel trhat the problem is that ASM1 (for node 1) or ASM2 (for node 2) already exists. However, I can not find either of these. What did you see?
crs_stat
srvctl status asm -n node01
srvctl status asm -n node02
if you see asm on node01/node2... you can start them if thet offline
srvctl start asm -n node01
srvctl start asm -n node02
and then.. use "DBCA" to help create ASM diskgroups.
I can create an ASM instance in single node mode, however, this creates an instance +ASM, which does not conflict.that can conflict.. don't start it (+ASM)
How do I find the non-existent instance, and remove it? (not in registry or services)
Alternatively, any other ideas as to what is happening?use "crs_stat" command
http://download.oracle.com/docs/cd/B28359_01/rac.111/b28255/crsref.htm#CWADD6025
and use "srvctl"
http://download.oracle.com/docs/cd/B28359_01/rac.111/b28254/srvctladmin.htm#RACAD028

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How to unbind raw devices used by ASM diskgroup?
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1. shutdown MYTEST database
2. in ASM instance, remove disks from diskgroup 'rawtest'
3. in ASM instance, "drop diskgroup rawtest including contents"
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Error setting raw device (Device or resource busy)
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Thanks,
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The installation guild will probably be were you will want to start.
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http://download.oracle.com/docs/cd/B19306_01/install.102/b15660/pre_install.htm#sthref457
Specifically
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http://download.oracle.com/docs/cd/B19306_01/install.102/b15660/pre_install.htm#sthref591

How to create a new ASM Diskgroup in Oracle 10g RAC?

Hi,
Our env is Oracle 10g R2 RAC on HP-UX. I want to create a new ASM Diskgroup. Please let me know if the following steps are ok to create a new ASM Diskgroup.
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2. From Node 1 ASM Instance issue the create diskgroup command.
SQL> create diskgroup DATA2 external redundancy disk '/dev/rdsk/c4t0d5';
3. Query v$asm_diskgroup and make sure the Diskgroup is created.
4. Mount the DATA2 Diskgroup from Node 2 ASM Instance.
5. Query v$asm_diskgroup and make sure the Diskgroup is visible from Node2 ASM instance.
6. Ensure the header_status is 'MEMBER'.
Rgds,

correct.
instead of using device file '/dev/rdsk/c4t0d5' you can create an alternate device file using mknod, which is called "asm_disk_xg" for example.
check here: http://download.oracle.com/docs/cd/B19306_01/install.102/b14202/storage.htm#CDEECIHI
hth

Question: 10gR2 database can not see the 11gR2 ASM diskgroup?

Hi there,
env:
uname -rm
2.6.18-92.1.22.el5xen x86_64
Single server(non-RAC)
note: we don't want to upgrade 10gr2 database into 11gR2 yet. But we created the 11gR2 ASM, then a 11gr2 database on ASM, and plan to migrate datafile in 10gR2 database to 11gR2 ASM
1. oracle 10gR2 installed first version: 10.2.0.3.0
2. then install 11gR2 Grid Infrastructure, and created ASM (version 11gr2)
$ sqlplus / as sysasm
SQL*Plus: Release 11.2.0.1.0 Production on Tue Oct 19 10:30:56 2010
Copyright (c) 1982, 2009, Oracle. All rights reserved.
Connected to:
Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - 64bit Production
With the Automatic Storage Management option
SQL> col name form a15
SQL> col COMPATIBILITY form a15
SQL> col DATABASE_COMPATIBILITY form a15
SQL> l
1* select name , STATE, COMPATIBILITY, DATABASE_COMPATIBILITY from v$asm_diskgroup
SQL> /
NAME STATE COMPATIBILITY DATABASE_COMPAT
ORCL_DATA1 MOUNTED 11.2.0.0.0 10.1.0.0.0
ORA_DATA MOUNTED 10.1.0.0.0 10.1.0.0.0
3. in 10gR2 database
sqlplus /
SQL*Plus: Release 10.2.0.3.0 - Production on Tue Oct 19 12:12:31 2010
Copyright (c) 1982, 2006, Oracle. All Rights Reserved.
Connected to:
Oracle Database 10g Enterprise Edition Release 10.2.0.3.0 - 64bit Production
With the Partitioning and Data Mining options
SQL> select * from v$asm_diskgroup;
no rows selected
4. pin the node into css
# /u01/app/product/11.2.0/grid/bin/crsctl pin css -n mynodename
CRS-4000: Command Pin failed, or completed with errors.
Question: 10gR2 database can not see the 11gR2 ASM diskgroup?
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Thanks
Scott

What is the output of
olsnodes -t -n
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Hi
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Internal Error Information:
Category: 1234
Operation: scls_scr_create
Location: mkdir
Other: Unable to make user dir
Dep: 2
Successfully accumulated necessary OCR keys.
Creating OCR keys for user 'root', privgrp 'root'..
Operation successful.
Configuration for local CSS has been initialized
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Hi thanks,
I have passed more steps, CSS is started after changing the hostname, after that I created two drive and mounted properly
when I try to create a ASM disk its failing with following error and idea
SQL> CREATE DISKGROUP DB_DATA NORMAL REDUNDANCY
2 FAILGROUP controller1 DISK '/dev/dsk/c0d1s0'
3 FAILGROUP controller2 DISK '/dev/dsk/c1d1s0';
CREATE DISKGROUP DB_DATA NORMAL REDUNDANCY
ERROR at line 1:
ORA-15018: diskgroup cannot be created
ORA-15031: disk specification '/dev/dsk/c1d1s0' matches no disks
ORA-15025: could not open disk '/dev/dsk/c1d1s0'
ORA-15056: additional error message
Intel SVR4 UNIX Error: 13: Permission denied
Additional information: 42
Additional information: 134497888
Additional information: -809278080
ORA-15031: disk specification '/dev/dsk/c0d1s0' matches no disks
ORA-15025: could not open disk '/dev/dsk/c0d1s0'
ORA-27037: unable to obtain file status
Intel SVR4 UNIX Error: 25: Inappropriate ioctl for device
Additional information: 16
Additional information: 134497888
Additional information: -809278080

"Best" Allocation Unit Size (AU_SIZE) for ASM diskgroups when using NetApp

We're building a new non-RAC 11.2.0.3 system on x86-64 RHEL 5.7 with ASM diskgroups stored on a NetApp device (don't know the model # since we are not storage admins but can get it if that would be helpful). The system is not a data warehouse--more of a hybrid than pure OLTP or OLAP.
In Oracle® Database Storage Administrator's Guide 11g Release 2 (11.2) E10500-02, Oracle recommends using allocation unit (AU) size of 4MB (vs. a default of 1MB) for a disk group be set to 4 MB to enhance performance. However, to take advantage of the au_size benefits, it also says the operating system (OS) I/O size should be set "to the largest possible size."
http://docs.oracle.com/cd/E16338_01/server.112/e10500/asmdiskgrps.htm
Since we're using NetApp as the underlying storage, what should we ask our storage and sysadmins (we don't manage the physical storage or the OS) to do:
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* What do they need to confirm and/or set regarding I/O on the NetApp side?
On some other 11.2.0.2 systems that use ASM diskgroups, I checked v$asm_diskgroup and see we're currently using a 1MB Allocation Unit Size. The diskgroups are on an HP EVA SAN. I don't recall, when creating the diskgroups via asmca, if we were even given an option to change the AU size. We're inclined to go with Oracle's recommendation of 4MB. But we're concerned there may be a mismatch on the OS side (either Redhat or the NetApp device's OS). Would rather "first do no harm" and stick with the default of 1MB before going with 4MB and not knowing the consequences. Also, when we create diskgroups we set Redundancy to External--because we'd like the NetApp device to handle this. Don't know if that matters regarding AU Size.
Hope this makes sense. Please let me know if there is any other info I can provide.

Thanks Dan. I suspected as much due to the absence of info out there on this particular topic. I hear you on the comparsion with deviating from a tried-and-true standard 8K Oracle block size. Probably not worth the hassle. I don't know of any particular justification with this system to bump up the AU size--especially if this is an esoteric and little-used technique. The only justification is official Oracle documentation suggesting the value change. Since it seems you can't change an ASM Diskgroup's AU size once you create it, and since we won't have time to benchmark using different AU sizes, I would prefer to err on the side of caution--e.g. first do no harm.
Does anyone out there use something larger than a 1MB AU size? If so, why? And did you benchmark between the standard size and the size you chose? What performance results did you observe?

Disaster Recovery with different ASM diskgroups

Hi@all,
actually I'm trying to test a Disaster Recovery Scenario. At a Oracle Linux 6 server with installed Grid Infra 12c and Ora Database 11.2.0.4 (there is also a 12.1.0.2 database instance) I'm trying to do a disaster recovery. But I'm getting wild by restoring and recovering the database. The problem here is, that the ASM diskgroup name has changed. As you read out I also switched the physical server, but I think that shouldn't be any problem.
At the old server I've two ASM diskgroups "+DATA" and "+FRA_1", at the new they're called "+DATA_SRVNAME" and "+FRA_SRVNAME". I've already changed the startup parameter in spfile, but now after restoring the controlfile RMAN has the directions to the old diksgroup:
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using target database control file instead of recovery catalog
RMAN-06139: WARNING: control file is not current for REPORT SCHEMA
Report of database schema for database with db_unique_name SID
List of Permanent Datafiles
===========================
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1    0        SYSTEM               ***     +DATA/SID/datafile/system.438.816606399
So I've tried three ways. First was to rename the datafile name:
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Second was to set the newname in RMAN:
set newname for datafile 16 to '+DATA_SRVNAME/SID/datafile/mms_basic_tab.455.816617697/';
And second was to recreate the controlfile with
CREATE CONTROLFILE REUSE DATABASE "SID" RESETLOGS ARCHIVELOG
    MAXLOGFILES 16
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'+DATASRVNAME/SID/datafile/system.438.816606399',
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So now my question to you: How am I able to tell the controlfile or database to use the other ASM diskgroup?
I know, easiest way would be to create a diskgroup +DATA and do the restore / recover, but at the new server I've no more storage to assign to a new diskgroup and because of there are running other instances I would'nt change the ASM diskgroups.
Did you have anny solution?
Thanks a lot and Regards,
Dave

Please try this
RMAN> run
set newname for datafile 1 to '+DATA_SRVNAME';
restore datafile 1;
switch datafile 1;
recover datafile 1;
Did you created +DATA_SRVNAME diskgroup?
and

Asm diskgroup really full?

Hi gurus,
after install RAC (11.2.0.3 two nodes) on linux, a warning appears shown a diskgroup almost full:
SQL> select group_number, name, block_size, state, total_mb, free_mb, hot_used_mb from V$ASM_DISKGROUP WHERE NAME='VOL';
GROUP_NUMBER NAME                           BLOCK_SIZE STATE         TOTAL_MB      FREE_MB HOT_USED_MB
           4 VOL                          4096 MOUNTED          23838       284           0correctly, It's looks like almost full.
It is a new RAC database, if i check any file at asmcmd:
asmcmd> cd VOL
asmcmd> ls
asmcmd>no files appear, so i go to asmca and check:
ASM CLUSTER FILE SYSTEM
ACTIVE MOUNT POINT | STATE | ALL_MOUNT_POINTS | VOLUME DEVICE    | SIZE (GB) | VOLUME | DISK_GROUP | USED (%)
/backup                 MOUNTED   /backup           /dev/asm/vol-24   22.91      VOL VOL       4.19it's only 4.19% in use
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ASM and ACFS are related (an ACFS volume is part of an ASM diskgroup), but not the same
you have ASM diskgroup with 23 GB storage
you created an ACFS volume on it with ~23 GB size
from ASM point of view, the diskgroup is almost full, because of the ACFS volume
from ACFS point of view, its empty, because you didnt put anything yet on that volume
its similar as LVM
you create a volume group (ASM diskgroup in this analogy) with 23 GB size
then you create a volume (ACFS volume in this analogy) with nearly 23 GB size
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Can I partition a LUN into 2 and create 2 diskgroups

Hi everyone.
I have a LUN that I want to share the space across 2 ASM diskgroups.
The LUN is from an EMC SNA and presented using multipathing, and appears as device emcpowera
Normally, I would create a single diskgroup per LUN, but in this case, is there any reason why I cant do the following?
1. fdisk /dev/emcpowera and create 2 equal size partions
2. oracleasm createdisk DG_DATA1 /dev/emcpowera1
3. oracleasm createdisk DG_DATA2 /dev/emcpowera2
4. Create diskgroups on each of DG_DATA1 and DG_DATA2 ?
Thanks

Hi,
While 2 diskgroups (one for DATA and one for FRA) is best practices from Oracle:
http://www.oracle.com/technetwork/database/asm-10gr2-bestpractices.pdf
I personally would not go with only one LUN per diskgroup.
2 reasons:
-> It is best practice that all LUNs in a diskgroup should be approximately the same size, since ASM will automatically re balance the diskgroup based on a percentage for filling.
And if you need to increase the space it is more difficult to increase a lun online (since some processes might not be accepting the change without a reboot), than to simply add another one.
Now if you take one big LUN and need space (and choose not to increase the volume) you should add a LUN with the same size... resulting in maybe waisting a lot of space, just for a few megabytes needed additionally.
So I vote for using more (around 4) LUNs just to be more flexible in increasing the space.
-> Second reason are the I/O characteristica of the OS. Sometimes it is easier for an OS to handle the I/O if there are multiple LUNs than just one.
PS: It is totally o.k. to leave the mirroring to the storage system (if no other special requirements, like host based mirroring are needed) and use extarnal redundancy.
Just my 2 cents...
Sebastian

How to rename ASM diskgroups after having cloned the original disks to the same server. ASMlib is used

Linux RHE 6
Oracle Grid single instance (Oracle Restart) 11.2.0.4 installed
Oracle RDBMS 11.2.0.4 installed
One 11.2.0.4 database single instance running
Our ASM have DATA, REDO, FRA diskgroup mounted
We need to do a storage snapshot for creating on THE SAME server a copy of the current ASM diskgroups DATA, REDO, FRA. Then we would rename the cloned diskgroups using renamedg command.
We have done this operation several times when ASMlib is not used. The command used when ASMlib is not used is for example:
renamedg dgname=FRA newdgname=FRA2 verbose=true phase=both asm_diskstring='/dev/oracle/fra*'
With ASMlib in use I am not sure about the steps to follow
First I am not sure about what to provide to the asm_diskstring parameter of the renamedg command. I need to provide an asm_diskstring which identifies the path pointing to the disks belonging to the cloned diskgroup (I do not want to rename the original diskgroup). Though in an ASM instance using ASMlib the parameter asm_diskstring is is ‘ORCL:*’.
Second, I suppose after the diskgroup rename ASMlib would return an error because it would find duplicated disks.
Could you please advise ?
Thanks in advance
Massi

Hi,
As you have OS level clone ,you have same ASMlib label.
ASMlib always mount unique ASMLib label only.
+you need to identify those newly cloned device.
+ Then rename those ASMLib label using force-renamedisk after taking 1Mb disk backup using dd read on one node .
+ Then run scandisks on other nodes .
+ Then validate newly labelled device is mounted or not on all nodes .
$ ls -ltr /dev/oracleasm/disks/*
+ Then run renamedg command with asm_diskstring of /dev/oracleasm/disks/*
Regards,
Aritra

Recommended Number LUNs for ASM Diskgroup

We are installation Oracle Clusterware 11g, Oracle ASM 11g and Oracle Database 11g R1 (11.1.0.6) Enterprise Edition with RAC option. We have EMC Clariion CX-3 SAN for shared storage (All oracle software will reside on locally). We are trying to determine the recommended or best practice number of LUNs and LUN size for ASM Diskgroups. I have found only the following specific to ASM 11g:
ASM Deployment Best Practice
Use diskgroups with four or more disks, and making sure these disks span several backend disk adapters.
1) Recommended number of LUNs?
2) Recommended size of LUNs?
3) In the ASM Deployment Best Practice above, "four or more disks" for a diskgroup, is this referring to LUNs (4 LUNs) or one LUN with 4 physical spindles?
4) Should the number of physical spindles in LUN be even numbered? Does it matter?

user10437903 wrote:
Use diskgroups with four or more disks, and making sure these disks span several backend disk adapters.This means that the LUNs (disks) should be created over multiple SCSI adapters in the storage box. EMCs have multiple SCSI channels to which disks are attached. Best practice says that the disks/luns that you assing to a diskgroup should be spread over as many channels in the storage box as possible. This increases the bandwidth and therefore, performance.
1) Recommended number of LUNs?Like the best practice says, if possible, at least 4
2) Recommended size of LUNs?That depends on your situation. If you are planning a database of 100GB, then a LUN size of 50GB is a bit overkill.
3) In the ASM Deployment Best Practice above, "four or more disks" for a diskgroup, is this referring to LUNs (4 LUNs) or one LUN with 4 physical spindles?LUNs, spindles if you have only access to physical spindles
4) Should the number of physical spindles in LUN be even numbered? Does it matter?If you are using RAID5, I'd advise to keep a 4+1 spindle allocation, but it might not be possible to realize that. It all depends on the storage solution and how far you can go in configuring it.
Arnoud Roth

Creating ASM for test purpose

hi all,
I am trying to setup ASM for test purpose on winxp with oracle 10g release 1.
I have created asm instance with
oradim -NEW -ASMSID +ASM -STARTMODE auto
and my pfile located in E:\oracle\product\10.1.0\Db_1\database looks like.
INSTANCE_TYPE=ASM
ASMALLOW_ONLY_RAW_DISKS = FALSE
DB_UNIQUE_NAME = +ASM
ASM_DISKSTRING ='E:\asmdisks\*'
LARGE_POOL_SIZE = 16M
BACKGROUND_DUMP_DEST ='E:\oracle\product\10.1.0\admin\+ASM\bdump'
USER_DUMP_DEST = 'E:\oracle\product\10.1.0\admin\+ASM\udump'
CORE_DUMP_DEST = 'E:\oracle\product\10.1.0\admin\+ASM\cdump'
I have created 3 disks with following commands
asmtool -create e:\asmdisks\disk1 512
asmtool -create e:\asmdisks\disk2 512
asmtool -create e:\asmdisks\disk3 512
now when i do
SET ORACLE_SID=+ASM
and
sqlplus / as sysdba
I get
SQL> select path, mount_status from v$asm_disk;
no row selected.
and for obvious reasons I get following message
SQL> create diskgroup data external redundancy disk
2 'E:\asmdisks\disk1';
create diskgroup data external redundancy disk
ERROR at line 1:
ORA-15018: diskgroup cannot be created
ORA-15031: disk specification 'E:\asmdisks\disk1' matches no disks
ORA-15025: could not open disk 'E:\ASMDISKS\DISK1'
ORA-15059: invalid device type for ASM disk
OSD-04018: Unable to access the specified directory or device.
O/S-Error: (OS 1200) The specified device name is invalid.
Please guide me..I am very new to ASM .

Hi all,
my problem got resolved.
I have created same fake disks by asmtool and the created diskgroups by "create diskgroup.. " then I was able to see the diks in v$asm_disk view..
I have successfully migrated my database to ASM if u have any questions do mail me @ [email protected].

Creating asm diskgroup

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