ASM Question

Just want to get an idea of how people are configuring the underlying disks with ASM. I've seen multiple studys/articles/etc showing very little difference between using RAID1 and RAID10, ASM doesn't seem to care. My storage admin is giving me some pushback b/c at RAID1 (whole disks), he has a RAID group for each LUN that I want to use, so with 20 disks (20 mirrors), he has to create 20 RAID groups/LUNs, he would rather just put all 40 disks into a RAID10 group and create 1 massive LUN to present to ASM. I don't think ASM cares either way, it's a matter of letting the SAN stripe (RAID10) or letting ASM stripe (RAID1). Anybody give me some real world examples of what you're doing or have seen customers doing? Thanks.

Well your controlfiles are in right place. Oracle created a link "+TUNOP_DISK_GROUP_001/LETO/control01.ctl " which is the filename specified in init.ora to point to "control01.ctl => +TUNOP_DISK_GROUP_001/LETO/CONTROLFILE/Current.256.585244865" which is the actual filename in ASM instance.
Read oracle doc for more on asm aliases.
Daljit Singh

Similar Messages

DataGuard and ASM Question

I want to implement Dataguard between non-asm instances. My question is how to move data from non-asm to asm box.
Thanks,

Sure. The location of the data files is irrelevent to DataGuard-- DataGuard is only concerned with the change vectors (i.e. the redo information).
Justin

Oracle 10gR2 RAC - ASM question

Hi
I have a question regarding the ASM storage. Let says I have a system here running Oracle 10gR2 RAC and would like to add a new/extend the current DATA disk group with more disk space. How do I do that? will it affect the existing data stored inside there?

So to add a little more to the discussion. Let's say your storage administrator presents you a LUN and is nice enough to add a partition of say 7G. (/dev/sdo1).
Now you need to take /dev/sdo1 stamp it and alter your storage group.
For illustration purposes I shall use rac1 and rac2 as my dual instance RAC and add to the asm group ARCH.
As root on rac1
/etc/init.d/oracleasm createdisk ARCH2 /dev/sdo1
then run
/etc/init.d/oracleasm listdisks
to make sure ARCH2 shows up.
On rac2 you run
/etc/init.d/oracleasm listdisks
You don't see ARCH2 so then run
/etc/init.d/oracleasm scandisks
then
/etc/init.d/oracleasm listdisks
Now you should see ARCH2
Ok the asm stamps are in sync now.
Back to rac1
su - oracle
set ORACLE_SID to asm instance and use sqlplus
sqlplus / as sysasm
If you query V$ASM_DISK you will see your disk with a header_status of PROVISIONED
that's good ...
NOw while still in sqlplus
Let's bump up the asm_power_limit so rebalancing runs faster
alter system set asm_power_limit=5 scope=both ;
If your asm instance are sharing the same spfile you only need do this on one instance; otherwise run the command both on all asm instances.
Lastly
ALTER DISKGROUP ARCH ADD DISK 'ORCL:ARCH2' ;
Now you can query V$ASM_OPERATION and watch ASM do it's magic of rebalancing.
That's it. All done while the DB is up and running.
How does that work for you?
-JR jr

Clustered ASM question

Can you have clustered ASM instance (RAC) with 2 nodes, but each node to use local storage only (local disks only) and somehow share it with other node?
Hope question is clear enough.
Let's say I have two physical machines but no money for anything attached (NAS,SAN,NFS). Just those two machines and make them somehow clustered ASM storage.
Sorry for asking stupid questions ... still newbe
10gR2 + Linux x86

I am not aware of anything like that. BUt for testing purpose you can use whats called an openfiler...below is out of the doc
Powered by rPath Linux, Openfiler is a free browser-based network storage management utility that delivers file-based Network Attached Storage (NAS) and block-based Storage Area Networking (SAN) in a single framework.
http://www.oracle.com/technology/pub/articles/hunter_rac10gr2_iscsi.html

ASM question for Diskgroup not complete

Hi guys
Currently i am trying to solve a problem that is created by me in order for me to handle a real scenario. For example, there are three failgroups and each failgroup has 3 disks in window environment(VMWARE).
Diskgroup DATA
Failgroup 1: A, B and C
failgroup 2: D, E and F
failgroup 3: G, H, I
When i removed drive I (simulate a hard disk failure), the DATA diskgroup would not mount. If i tried to mount the diskgroup DATA, i would receive an error message like "DISKgroup not complete, ASM disk 6 and 4 missing". If i added a new disk for example T, i would receive an error message such as "diskgroup DATA does not exist or is not mounted". But if i added the disk I back, i would able to mount the DISKGROUP. Can anyone tell me how i can deal with this kind of situation without adding back the old disk I ?

Hi
I am not too sure about how ASM is able to handle disk failure
For example in ASM confiiguration :
Diskgroup DATA (Normal redundance) consists of 3 Failgroups:
Failgroup 1: A, B and C
failgroup 2: D, E and F
failgroup 3: G, H, I
Now lets assume Disk I fails. For ASM configuration, Data will be rebalanced within the Failgroup 3 to keep up normal redundancy. By right, the database is still online and is able to handle users.
But for my case:
When i removed drive I (simulate a hard disk failure) and start up the instance, the diskgroup would not mount. If i tried to mount the diskgroup DATA, i would receive an error message like "DISKgroup not complete, ASM disk 1 missing". ---> At this point, I thought ASM should able to handle disk failure and the diskgroup should be able to handle missing disk.
But if i added the original disk I back and start the vmware, i would able to mount the DISKGROUP. I was trying to make sure ASM configuration can handle disk failure.
How can i be too sure that ASM instance is able to handle disk failure if DISK I fails --->

Installation with ASM question

In reading one of the ASM install docs it says to install the OS and the Oracle home on the same drive. Is this really a requirement? The client is a windows shop, OS is Windows 2008 R1, Oracle 11.1.0.7. We want to install the OS on one drive and the Oracle home on another, will that cause issues for ASM?
Thanks in advance.

I do not think so. You should be able to install your ORACLE_HOME on a different partition or drive. Just out of curiosity: where exactly did you read this?
Bjoern

SSD and ASM configurations

Hello all,
Although I realize that the question of configuration on ASM regarding the use of SSD storage devices is, or should be mote at this point.
I still see, from time to time, questions and discussions on this topic in the other forms.
I am wondering if it would be possible to create such a forum just to discuss these questions?
But then where do you put it?
Should this be a storage section for SSD?
Database ASM storage or a subset or either?
What do you think?

smitty8 wrote:
Hello all,
< snip >
But then where do you put it?
No.
If you have an ASM question, post it to the ASM discussion space.
If you happen to have a question dealing with a Sun/Oracle branded piece of storage hardware such as an array or a tape library, it goes here.
You posted today's question to the storage HARDWARE discussion space.
It doesn't belong here.
Edit:
... and because you multi-cross-posted
https://community.oracle.com/thread/3618609
this thread is locked.

/var filesystem full according to df but not du command? How do you resolve this?

Environment is a 2 node cluster, one node is running Oracle DB and the other running Oracle AS. Node running Oracle AS has /var of about 9.9G. /var is an independent filesystem and not part of /. After rebooting or when there are no users accessing the application, /var is about 2.4G and this is reflected on both df and du commands. But afew minutes into application usage and that shoots up to 100% capacity utilization reflected in df -h command output but du still hovers around 2.4G. I know to resolve this scenario you look for open but deleted files i.e. files with a link count of 0 using
find /proc/*/fd -type f -links 0 | xargs du -k | sort -n
They are binary files, application related I suppose but when I view them with cat command I get to make out a few details in plain text. I decided to delete one as a test case and see if it affected any real data, surprisingly it did. How is this possible if link count is zero? Has anyone experienced such a scenario before? I can't apply the resolution to this problem without affecting data so am in quite a fix
Note: I know nothing about Oracle AS

user10980710 wrote:
Environment is a 2 node cluster, one node is running Oracle DB and the other running Oracle AS.
That's not a cluster. That's simply two different servers, each with its own distinct function.
Node running Oracle AS has /var of about 9.9G. /var is an independent filesystem and not part of /. After rebooting or when there are no users accessing the application, /var is about 2.4G and this is reflected on both df and du commands. But afew minutes into application usage and that shoots up to 100% capacity utilization reflected in df -h command output but du still hovers around 2.4G. I know to resolve this scenario you look for open but deleted files i.e. files with a link count of 0 using
find /proc/*/fd -type f -links 0 | xargs du -k | sort -n
They are binary files, application related I suppose but when I view them with cat command I get to make out a few details in plain text. I decided to delete one as a test case and see if it affected any real data, surprisingly it did. How is this possible if link count is zero? Has anyone experienced such a scenario before? I can't apply the resolution to this problem without affecting data so am in quite a fix
Note: I know nothing about Oracle AS
So where is the ASM question here? (This is the ASM forum). Looks to me like this would be better addressed in a Linux forum, of which there are several on the Web, both within OTN and outside.

Protection level "resynchronization"

Have a physical standby setup - oracle 11.2.01 on linux - with active dataguard. All's been fine for a long while. There were performance issues on the standby server (also the home for other databases besides the dg standby). Someone tried using different physical ports and dataguard lost communication. Anyway, there were many logs not transported when I looked at it. In the broker it pointed to a redo transport issue which probably resulted from the network work being done. The database was set to maxavailability with 'SYNC' . So what do I do to get the thing sending logs again? I read to restart the standby which I did but that had no effect. Another person here wanted to set to maxperformance but when we downgraded to that, just the current log got sent and not all the others that needed to.
I'm thinking I might have to manually copy over these logs. Does anyone know if that will be the case?
The protection mode had been maxavailability and the protection level had been "resynchronization". Once I issued the command to set to max performance, now I get
SQL> select protection_mode, protection_level from v$database;
PROTECTION_MODE PROTECTION_LEVEL
MAXIMUM PERFORMANCE MAXIMUM PERFORMANCE
which is fine but like I said - many old logs need to be moved.
Also, both databases use ASM. If I do need to copy over is there a way to copy from asm on one server directly to asm on another or do I need to go to OS files in the middle?

So you have a log gap right? I would copy the archived redo from the primary over to the standby site and register them.
You probably have this: (RUN ON STANDBY)
SELECT MAX(R.SEQUENCE#) LAST_SEQ_RECD, MAX(L.SEQUENCE#) LAST_SEQ_SENT
FROM V$ARCHIVED_LOG R, V$LOG L
WHERE R.DEST_ID=2 AND L.ARCHIVED='YES';
I cannot speak to the ASM question.

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?
please help
Thanks
Scott

What is the output of
olsnodes -t -n
Also, see unix error log and ohasd error log if you find anything in that

Questions on asm disk discovery:

Questions on asm disk discovery:
1）What is the relationship btween asm_diskstring in the init.ora and DiscoveryString in the GPNP profile.xml?
2) Which one of the above two finally accounts for the disk discovery process?
3) We know that asmlib disks are self describing at the disk header. This overcomes the disk name/path persistency issue as we no long need to rely on the path to discover the asm disks, by setting asm_diskstring='ORCL:*' , ASM instance will identify the right disks automatically. However, I am not sure if setting asm_diskstring='ORCL:*' is the most economic way to do the discovery as I am not sure if Oracle will have to probe all the disks on the OS to determine the right disks. If Oracle has to screen all the disks in this way, then I think setting asm_diskstring='<path_to_asmlib_disk>' will be much faster, although this will be open to the persistent problem. Is my understanding correct?
Thanks.

From my understanding all disk you see in /dev/oracleasm/disks are the disks in your system that been discovered by asmlib at discovery stage.
Currently, due to bug 13465545, ASM instance will discover disks from both locations, ASM_DISKSTRING and gpnp profile, which can cause some mess in disk representation for asm. You can check the settings using asmcmd command: dsget, and set to be the same using dsset.
I think its more secure to set ASM_DISKSTRING to only the disks used by asm instance.
ASMCMD> dsget
Regards
Ed

Questions on asm disk discover:

Questions on asm disk discover:
1）What is the relationship btween asm_diskstring in the init.ora and DiscoveryString in the GPNP profile.xml?
2) which one finally accounts for the disk discovery process?
3) We know that asmlib disks are self describing at the disk header. This overcomes the disk name/path persistency issue as we do not rely on the path the discover the asmlib
disks. asm_diskstring='ORCL:*' will identify the right disks. I am not sure if setting 'ORCL:*' is the most economic way as I am not sure if Oracle will have to scan all the disks
on the OS and probe the disks that it has rigths to determine which disks belong to ASM. If Oracle has to screen all the disks in this way, then I think setting
asm_diskstring='<path_to_asmlib_disk>' will be much faster. However, this will be open to the persistent problem. Is my understanding correct?
Thanks.

Questions on asm disk discovery:
1）What is the relationship btween asm_diskstring in the init.ora and DiscoveryString in the GPNP profile.xml?
2) Which one of the above two finally accounts for the disk discovery process?
3) We know that asmlib disks are self describing at the disk header. This overcomes the disk name/path persistency issue as we no long need to rely on the path to discover the asm disks, by setting asm_diskstring='ORCL:*' , ASM instance will identify the right disks automatically. However, I am not sure if setting asm_diskstring='ORCL:*' is the most economic way to do the discovery as I am not sure if Oracle will have to probe all the disks on the OS to determine the right disks. If Oracle has to screen all the disks in this way, then I think setting asm_diskstring='<path_to_asmlib_disk>' will be much faster, although this will be open to the persistent problem. Is my understanding correct?
Thanks.

Looking for information on the below questions on ASM

Scenario: (Oracle 10g on Windows 2003 with EMC storage)
ASM Partition table crashed for LUN 20 on 18th July
DB was up and running till 23rd July (New LUN (LUN 36) was presented and the RMAN backup used to restore the data that were residing on the corrupt LUN)
End of the day everything screwed up and the complete grid (4 nodes) was rebuild.
Links:
As mentioned in the link: http://www.exforsys.com/forum/oracle-database/487-what-asm-instance-oracle.html
"The ASM instance is only involved during the creation or deletion of files and when disk configurations change (such as dropping or adding a disk). When these types
of changes occur, the ASM instance automatically rebalanced the disks and provides the necessary information to refresh the extent map in the SGA of the database
instance. Of course, this process requires that the ASM instance run concurrently with the database instance, and only shut down after the database instance is
closed."
As mentioned in the link: http://www.orafaq.com/wiki/ASM_FAQ#ASM_disk_header.2Fsuperblock_backups.3F
"ASM disk headers (super-blocks) cannot be backed up and restored in Oracle 10g. By implication, if you use EXTERNAL REDUNDANCY and a single disk's header is
accidentally overwritten, the entire disk group will have to be restored."
As mentioned in the link: http://www.datadisk.co.uk/html_docs/oracle/asm.htm
"ASM is a special instance that does not have any data files, there is only ASM instance one per server which manages all ASM files for each database. The instance
looks after the disk groups and allows access to the ASM files. Databases access the files directly but uses the ASM instance to locate them. If the ASM instance is
shutdown then the database will either be automatically shutdown or crash. "
With the above scenario and the documents provided in the links above, I am unable to get the complete picture of what went wrong. Will be great if some one could
through more light on the below questions. (Note: we have multiple vendor engaged managing different part of this outage and unable to get the real fact of what went
wrong)
1, The ASM had given the details of the disk to the DB, and the DB is managing the disk directly. Also the DB and the ASM instance were up and running till 23rd is
what i understand going by the details given in the above links, in this scenario how can we confirm that the partition table is corrupt / missing. Is their a way to
check the same?
2, ASM disk headers (super-blocks) cannot be backed up, that means that it can not be read directly. Then is it possible to say that the ASM disk header is corrupt /
missing?
3, If the ASM disk header / partition table of LUN 20 is corrupt on 18th, can the DB run till 23rd without any issue? will the ASM & DB does not crash?
4, ASM will strip the data across the available LUN's, will it not be able to rebuild the data on the newly presented LUN 36 instead of using RMAN backup to rebuild the
data? or is the ASM not configured as it should be done. (WE have multiple LUN's presented to this Grid)
Edited by: 880333 on Aug 19, 2011 12:35 AM

What relation with the Oracle Forms product ?
Francois

Controlfile on ASM performance question

Seeing Controlfile Enqueue performance spikes, consideration are to move control file to separater diskgroup(need outage) ? or add some disk(from different luns,( i prefer this approach) in the same disk group , seems like slow disk is casing this issue...
2nd question :can snapshot controlfile be placed on ASM storage?

Following points may help:
- Separating the control file to another diskgroup may make things even worse in case that the total number of disks are insufficient in the new disk group.
- Those control file contention issues are usually nothing to do with the storage throughput you have but the number of operations requiring different levels of exclusion on the control files.
- Since multiple copies of controlfiles are updated concurrently a possible, sometimes, problem is that the secondary copy of controlfile is slower than the other. Please check that this is not the issue (different tiers of storage may cause such problems)
Regards,
Husnu Sensoy

ASM Disk Remove/Add Question

Hello All,
I have a quick question -
We have an ASM Diskgroup that had 8 Disks in it. I removed 2 Diskss and the Diskgroup has been rebalanced. I have not done anything with the removed Disks.
They both appear in the ASM target as eligble to add back into the Diskgroup.
Do I need to re-format/partition/create disk on them before adding them back in? Would existing data on the Diskl cause an issue in the Diskgroup?
This is the first time I will be adding back Disks that have been previously in the Diskgroup.
Thanks in advance for the advice.
Michele

Hi,
Disks eligible to be assigned to a diskgroup must have the status "CANDIDATE" or "FORMER" or "PROVISIONED".
· CANDIDATE - Disk is not part of a disk group and may be added to a disk group with the ALTER DISKGROUP statement
· PROVISIONED - Disk is not part of a disk group and may be added to a disk group with the ALTER DISKGROUP statement. The PROVISIONED header status is different from the
CANDIDATE header status in that PROVISIONED implies that an additional platform-specific action has been taken by an administrator to make the disk available for ASM.
· FORMER - Disk was once part of a disk group but has been dropped cleanly from the group. It may be added to a new disk group with the ALTER DISKGROUP statement.
The ALTER DISKGROUP...DROP DISK without WAIT option statement returns before the drop and rebalance operations are complete. Do not reuse, remove, or disconnect the dropped disk until the HEADER_STATUS column for this disk in the V$ASM_DISK view changes to FORMER.
You don't need change anything on OS Level. Oracle will reuse asmdisk dropped without needs perform any administrative task on OS Level.
Regards,
Levi Pereira

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