File system to ASM Migration

Currently we have unix file system for storage. We are planning to move to ASM. Based on documentation RMAN and physical standby could be the best way to migrate.
1. Is expdp/impdp an option?
2. Given an ASM env. is RMAN the only backup solution?
Thank you.

1. Yep. Doing it like that also lets you reorganize your tablespaces if you so desire. -
Let's say if I have 100 tablespaces.
a. create new tablespaces with diskgroups
b. Use impdp to import the data
2. RMAN main method; but could do something re breaking a mirror of a LUN
a. What do you mean by main method?
b. Can I not have online backups like snap clone (and/or offline the tblspace and move the datafiles?)
Appreciate your help.

Similar Messages

How to migrate 11gr2 standby database from file system to ASM

Hi,
I have 11gR2 data guard setup of 2 node RAC primary and stand alone standby database.
Primary RAC uses ASM, and stand alone standby DB uses normal file system for data files and archive logs. I want to migrate the stand alone standby DB from file system to ASM.
If you have any ideas or documents on it, kindly please share with me.
Thanks in advance,
Mahipal

Mahi wrote:
Hi Fran,
Thanks a lot for the quick reply. I have another question, I want to have standby in ASM; but ASM home is grid home(CRS+ASM) in 11gr2.
I don't want to configure CRS now for standby, only want to have ASM storage. s it possible to install the grid home only for ASM and not for CRS?
On a stand-alone system, there are still CRS/Grid components that are a part of the ASM install. You cannot NOT install it.
>
Thanks,
Mahi

File system and ASM

While I install oracle 11g release 2 the installer asked me :-
to choose between two types of storage
File system & Automatic Storage Management
I want to ask about the difference between them
How can I choose between them (depends on which factor(s))
any help will be appreciated
thanks a lot.

Hi;
After 10g oracle recommended to use ASM. Please read what is ASM and what is benefit:
http://docs.oracle.com/cd/B28359_01/server.111/b31107/asmcon.htm#BABDEIJI
http://docs.oracle.com/cd/B16276_01/doc/server.102/b14196/asm001.htm
File system vs ASM
http://www.oracle.com/technetwork/products/cloud-storage/acfs-technical-overview-514457.pdf
PS:Please dont forget to change thread status to answered if it possible when u belive your thread has been answered, it pretend to lose time of other forums user while they are searching open question which is not answered,thanks for understanding
Regard
Helios

How can I move back the rman convert file from file system to ASM?

I have no idea on pluging-in the data files which were unloaded as follows:
SQL> alter tablespace P_CDDH_DSPGD_V1_2011 read only;
SQL> alter tablespace P_IDX_CDDH_DSPGD_V1_2011 read only;
SQL> exec dbms_tts.transport_set_check('P_CDDH_DSPGD_V1_2011,P_IDX_CDDH_DSPGD_V1_2011',true);
SQL> select * from transport_set_violations;
UNIX> expdp tossadm@pmscdhf1 dumpfile=ttsfy1.dmp directory=trans_dir transport_tablespaces = P_CDDH_DSPGD_V1_2011,P_IDX_CDDH_DSPGD_V1_2011
RMAN> convert tablespace P_CDDH_DSPGD_V1_2011, P_IDX_CDDH_DSPGD_V1_2011 format = '/appl/oem/backup/temp/%I_%s_%t_extbspace.dbf';
Starting conversion at source at 03-OCT-13
using target database control file instead of recovery catalog
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=116 instance=pmscdhf11 device type=DISK
channel ORA_DISK_1: starting datafile conversion
input datafile file number=00079 name=+PMSCDHF1/p_cddh_dspgd_v1_2011_01.dbf
converted datafile=/appl/oem/backup/temp/3536350174_2820_827849001_extbspace.dbf
channel ORA_DISK_1: datafile conversion complete, elapsed time: 00:02:15
channel ORA_DISK_1: starting datafile conversion
input datafile file number=00080 name=+PMSCDHF1/p_idx_cddh_dspgd_v1_2011_02.dbf
converted datafile=/appl/oem/backup/temp/3536350174_2821_827849136_extbspace.dbf
channel ORA_DISK_1: datafile conversion complete, elapsed time: 00:01:45
Finished conversion at source at 03-OCT-13
Starting Control File Autobackup at 03-OCT-13
piece handle=/dbms/oracle/r1110/db_01/dbs/c-3536350174-20131003-02 comment=NONE
Finished Control File Autobackup at 03-OCT-13
SQL> drop tablespace P_CDDH_DSPGD_V1_2011 including contents;
SQL> drop tablespace P_IDX_CDDH_DSPGD_V1_2011 including contents;
Afterward, how can I relocate the backup files "/appl/oem/backup/temp/3536350174_2820_827849001_extbspace.dbf", "/appl/oem/backup/temp/3536350174_2821_827849136_extbspace.dbf" back to the ASM group +PMSCDHF1 ???

The 11.1 documentation only says "Enables you to copy files between ASM disk groups on local instances to and from remote instances" and "You can also use this command to copy files from ASM disk groups to the operating system."
http://docs.oracle.com/cd/B28359_01/server.111/b31107/asm_util.htm#CHDJEIEA
The 11.2 documentation says "Copy files from a disk group to the operating system Copy files from a disk group to a disk group Copy files from the operating system to a disk group"
http://docs.oracle.com/cd/E11882_01/server.112/e18951/asm_util003.htm#CHDJEIEA
I've never tried 11.1
Hemant K Chitale

Copy the SP2 Portal File System and then Migrate??

Hello All,
Is it possible to copy the EP6SP2 Portal FileSystem and the SQL Database on the other host and then migrate start the migration process from this host. I mean to create the export file from this new host(where we copied the fileSystem and the DB). Because anyways we have to shut down the portal while migrating, so i think this can be done..
Any ideas.
Vaib

Hi Vaib,
> That's my thread only
Totally right, I know. I just wanted to clean up the cross post particles
> Anyway...do you know
Not really, but check out https://www.sdn.sap.com/irj/servlet/prt/portal/prtroot/docs/library/uuid/b4e7b090-0201-0010-ada6-b9bc09c7f354 if it may help.
Hope it helps
Detlev

Moving spfile from non-asm to asm file system

Hi All
We are migrating non-asm file system to asm file system, we are held up in moving the spfile from non-asm file system to asm file system ...
we tried the below method
Recreate SPFILE on ASM diskgroup
SQL> create pfile='c:\initTEST.ora' from spfile;
File created.
SQL> create spfile='+DGRP2/spfileTEST.ora' from pfile='c:\initTEST.ora';
File created.
after this we started both the running instance and asm instance
but after starting the instance TEST we saw the instance still using spfile of non-asm file system
what is the correct way of moving the spfile from non-asm to asm file system..
Regards
Hariharan.T

You need to perform this first:
First rename the $ORACLE_HOME/dbs/spfileTEST.ora to spfileTEST.ora_old
create initTEST.ora in dbs location with below contents:
Also i recommend you to recreate the spfile in ASM as it might not be in good shape.
When ever you start the oracle instance there is a specific order to find the oracle pfile/spfile
1. O_H/dbs/spfile<SID>.ora
2. O_H/dbs/init<SID>.ora
3. O_H/dbs/spfile.ora
4. O_H/dbs/init.ora
in your case instance always finds spfileTEST.ora in dbs location (non -ASM) and will stop looking further. If you remove it our of the way it will find initTEST.ora which will redirect to spfile present in ASM.
NOTE: As per your earlier update you created spfile in ASM after puttin spfile='+DG...' in the initTEST.ora..
If you start the instance with this SPFILE you will be getting "maxmimum cursors limit exceeded" error.
-Ravi.M

Difference between ASM Disk Group, ADVM Volume and ACFS File system

Q1. What is the difference between an ASM Disk Group and an ADVM Volume ?
To my mind, an ASM Disk Group is effectively a logical volume for Database files ( including FRA files ).
11gR2 seems to have introduced the concepts of ADVM volumes and ACFS File Systems.
An 11gR2 ASM Disk Group can contain :
ASM Disks
ADVM volumes
ACFS file systems
Q2. ADVM volumes appear to be dynamic volumes.
However is this therefore not effectively layering a logical volume ( the ADVM volume ) beneath an ASM Disk Group ( conceptually a logical volume as well ) ?
Worse still if you have left ASM Disk Group Redundancy to the hardware RAID / SAN level ( as Oracle recommend ), you could effectively have 3 layers of logical disk ? ( ASM on top of ADVM on top of RAID/SAN ) ?
Q3. if it is 2 layers of logical disk ( i.e. ASM on top of ADVM ), what makes this better than 2 layers using a 3rd party volume manager ( eg ASM on top of 3rd party LVM ) - something Oracle encourages against ?
Q4. ACFS File systems, seem to be clustered file systems for non database files including ORACLE_HOMEs, application exe's etc ( but NOT GRID_HOME, OS root, OCR's or Voting disks )
Can you create / modify ACFS file systems using ASM.
The oracle toplogy diagram for ASM in the 11gR2 ASM Admin guide, shows ACFS as part of ASM. I am not sure from this if ACFS is part of ASM or ASM sits on top of ACFS ?
Q5. Connected to Q4. there seems to be a number of different ways, ACFS file systems can be created ? Which of the below are valid methods ?
through ASM ?
through native OS file system creation ?
through OEM ?
through acfsutil ?
my head is exploding
Any help and clarification greatly appreciated
Jim

Q1 - ADVM volume is a type of special file created in the ASM DG. Once created, it creates a block device on the OS itself that can be used just like any other block device. http://docs.oracle.com/cd/E16655_01/server.121/e17612/asmfilesystem.htm#OSTMG30000
Q2 - the asm disk group is a disk group, not really a logical volume. It combines attributes of both when used for database purposes, as the database and certain other applications know how to talk "ASM" protocol. However, you won't find any general purpose applications that can do so. In addition, some customers prefer to deal directly with file systems and volume devices, which ADVM is made to do. In your way of thinking, you could have 3 layers of logical disk, but each of them provides different attributes and characteristics. This is not a bad thing though, as each has a slightly different focus - os file system\device, database specific, and storage centric.
Q3 - ADVM is specifically developed to extend the characteristics of ASM for use by general OS applications. It understands the database performance characteristics and is tuned to work well in that situation. Because it is developed in house, it takes advantage of the ASM design model. Additionally, rather than having to contact multiple vendors for support, your support is limited to calling Oracle, a one-stop shop.
Q4 - You can create and modify ACFS file systems using command line tools and ASMCA. Creating and modifying logical volumes happens through SQL(ASM), asmcmd, and ASMCA. EM can also be used for both items. ACFS sits on top of ADVM, which is a file in an ASM disk group. ACFS is aware of the characteristics of ASM\ADVM volumes, and tunes it's IO to make best use of those characteristics.
Q5 - several ways:
1) Connect to ASM with SQL, use 'alter diskgroup add volume' as Mihael points out. This creates an ADVM volume. Then, format the volume using 'mkfs' (*nix) or acfsformat (windows).
2) Use ASMCA - A gui to create a volume and format a file system. Probably the easiest if your head is exploding.
3) Use 'asmcmd' to create a volume, and 'mkfs' to format the ACFS file system.
Here is information on ASMCA, with examples:
http://docs.oracle.com/cd/E16655_01/server.121/e17612/asmca_acfs.htm#OSTMG94348
Information on command line tools, with examples:
Basic Steps to Manage Oracle ACFS Systems

Unix shell: Environment variable works for file system but not for ASM path

We would like to switch from file system to ASM for data files of Oracle tablespaces. For the path of the data files, we have so far used environment variables, e.g.,
CREATE TABLESPACE BMA DATAFILE '${ORACLE_DB_DATA}/bma.dbf' SIZE 2M AUTOEXTEND ON;
This works just fine (from shell scripts, PL/SQL packages, etc.) if ORACLE_DB_DATA denotes a file system path, such as "/home/oracle", but doesn’t work if the environment variable denotes an ASM path like "\+DATA/rac/datafile". I assume that it has something to do with "+" being a special character in the shell. However, escaping "\+" didn’t work. I tried with both bash and ksh.
Oracle managed files (e.g., set DB_CREATE_FILE_DEST to +DATA/rac/datafile) would be an option. However, this would require changing quite a few scripts and programs. Therefore, I am looking for a solution with the environment variable. Any suggestions?
The example below is on a RAC Attack system (http://en.wikibooks.org/wiki/RAC_Attack_-OracleCluster_Database_at_Home). I get the same issues on Solaris/AIX/HP-UX on 11.2.0.3 also.
Thanks,
Martin
==== WORKS JUST FINE WITH ORACLE_DB_DATA DENOTING FILE SYSTEM PATH ====
collabn1:/home/oracle[RAC1]$ export ORACLE_DB_DATA=/home/oracle
collabn1:/home/oracle[RAC1]$ sqlplus "/ as sysdba"
SQL*Plus: Release 11.2.0.1.0 Production on Fri Aug 24 20:57:09 2012
Copyright (c) 1982, 2009, Oracle. All rights reserved.
Connected to:
Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - Production
With the Partitioning, Real Application Clusters, Automatic Storage Management, OLAP,
Data Mining and Real Application Testing options
SQL> CREATE TABLESPACE BMA DATAFILE '${ORACLE_DB_DATA}/bma.dbf' SIZE 2M AUTOEXTEND ON;
Tablespace created.
SQL> !ls -l ${ORACLE_DB_DATA}/bma.dbf
-rw-r----- 1 oracle asmadmin 2105344 Aug 24 20:57 /home/oracle/bma.dbf
SQL> drop tablespace bma including contents and datafiles;
==== DOESN’T WORK WITH ORACLE_DB_DATA DENOTING ASM PATH ====
collabn1:/home/oracle[RAC1]$ export ORACLE_DB_DATA="+DATA/rac/datafile"
collabn1:/home/oracle[RAC1]$ sqlplus "/ as sysdba"
SQL*Plus: Release 11.2.0.1.0 Production on Fri Aug 24 21:08:47 2012
Copyright (c) 1982, 2009, Oracle. All rights reserved.
Connected to:
Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - Production
With the Partitioning, Real Application Clusters, Automatic Storage Management, OLAP,
Data Mining and Real Application Testing options
SQL> CREATE TABLESPACE BMA DATAFILE '${ORACLE_DB_DATA}/bma.dbf' SIZE 2M AUTOEXTEND ON;
CREATE TABLESPACE BMA DATAFILE '${ORACLE_DB_DATA}/bma.dbf' SIZE 2M AUTOEXTEND ON
ERROR at line 1:
ORA-01119: error in creating database file '${ORACLE_DB_DATA}/bma.dbf'
ORA-27040: file create error, unable to create file
Linux Error: 2: No such file or directory
SQL> -- works if I substitute manually
SQL> CREATE TABLESPACE BMA DATAFILE '+DATA/rac/datafile/bma.dbf' SIZE 2M AUTOEXTEND ON;
Tablespace created.
SQL> drop tablespace bma including contents and datafiles;

My revised understanding is that it is not a shell issue with replacing +, but an Oracle problem. It appears that Oracle first checks whether the path starts with a "+" or not. If it does not (file system), it performs the normal environment variable resolution. If it does start with a "+" (ASM case), Oracle does not perform environment variable resolution. Escaping, such as "\+" instead of "+" doesn't work either.
To be more specific regarding my use case: I need the substitution to work from SQL*Plus scripts started with @script, PL/SQL packages with execute immediate, and optionally entered interactively in SQL*Plus.
Thanks,
Martin

DB_UNIQUE_NAME vs DB_NAME in standby databases of ASM file systems

Question : Do we need to have the db_unique_name paramter set differently in standby database compared to db_name in standby .
Problem we are facing :
Here is the little background
Primary Server     : SERVER1
db_name          : VENKAT
db_unique_name     : VENKAT
Standby server     : SERVER2
db_name          : VENKAT
db_unique_name     : VENKAT_stb
Sever          : Linux
Database Version: 11.20.3
File system type: ASM ( 11.2.0.3)
stanby type     : Physical
Disk group names: Identical on both primary and standby servers
Data          : +DATA_OP01027_128
FRA          : +FRA_VENKAT_128
How datafiles are layed out on primary server:
sample datafile name location : +DATA_VENKAT_128/VENKAT/datafile/venkat.277.789579565
How standby was build : using Active duplicte command
Once we have the standby database build we have the datafiles created under this location
Sample datafile name location on standby server : +DATA_VENKAT_128/VENKAT_stb/datafile/venkat.280.789579597
with this we have learnt that the directory VENKAT_stb is getting created in standby ASM off the db_unique_name that
was given in the database , we have not seen this issue in the normal file system even we are using db_unique_name different that
the db_name in standby database .
Can you please help us how we can prevent this situation of having datafiles getting created under differnt direction in standby compared to prod.
Can you also let us know what impacts we might be having if we don't specify the db_unique_name different than db_name in standby database.
Hope this explains the problem what we are facing currently .
What steps i follwed to fix this issues :
I have db_unique_name set to the same name as db_name and when i did the restore all datafiles are in the identical location to prod standby server .
Note : We do fully understand the need for having the db_unique_name set different to db_name in standby db in standby and primary db's are residing on the same physical server .
Thanks
Venkat

first of all, this is not an issue or problem
works as intended
Question : Do we need to have the db_unique_name paramter set differently in standby database compared to db_name in standby .yes
Sample datafile name location on standby server : +DATA_VENKAT_128/VENKAT_stb/datafile/venkat.280.789579597
with this we have learnt that the directory VENKAT_stb is getting created in standby ASM off the db_unique_name that
was given in the database , we have not seen this issue in the normal file system even we are using db_unique_name different that
the db_name in standby database .
Can you please help us how we can prevent this situation of having datafiles getting created under differnt direction in standby compared to prod.well, dont use OMF then
OMF format for datafiles in ASM is: +DISKGROUP/DB_UNIQUE_NAME/DATAFILE/TABLESPACE_NAME.FILE.INCARNATION
datafiles will be created this way no matter what you do
the difference is, that if you dont use OMF, there will be an alias created referencing the file, with the path you gave
for example:
OMF:
create tablespace test size 10M;
a datafile is created: +DATA_VENKAT_128/VENKAT/DATAFILE/test.280.789581212 (i wrote some random numbers here)
non-OMF:
create tablespace test datafile '+DATA_VENKAT_128/dummy/test01.dbf' size 10M;
what actually happens:
a datafile is created: +DATA_VENKAT_128/VENKAT/DATAFILE/test.280.789581212 (i wrote some random numbers here)
and an ASM alias is created: +DATA_VENKAT_128/dummy/test01.dbf
and this alias is used by the database
while OMF files have their specified path format, and their path (db_unique_name) and even name (numbers at the end) will change when duplicated, aliases dont necessarily do this
however this is just extra work and administration, OMF is your friend

Why would anyone want to use ASM Clustered File system?

DB Version: 11gR2
OS : Solaris, AIX, HP-UX
I've read about the new feature ACFS.
http://www.oracle-base.com/articles/11g/ACFS_11gR2.php
But why would anyone want to store database binaries in a separate Filesystem created by Oracle?

Hi Vitamind,
how do these binaries interact with the CPU when they want something to be done?
ACFS should work with Local OS (Solaris) to communicate with the CPU . Isn't this kind of double work?ACFS dont work with .... but provide filesystem to Local S.O
There may be extra work, but that's because there are more resources that a common filesystem.
Oracle ACFS executes on operating system platforms as a native file system technology supporting native operating system file system application programming interfaces (APIs).
ACFS is a general purpose POSIX compliant cluster file system. Being POSIX compliant, all operating system utilities we use with ext3 and other file systems can also be used with Oracle ACFS given it belongs to the same family of related standards.
ACFS Driver Model
An Oracle ACFS file system is installed as a dynamically loadable vendor operating system (OS) file system driver and tool set that is developed for each supported operating system platform. The driver is implemented as a Virtual File System (VFS) and processes all file and directory operations directed to a specific file system.
It makes sense you use the ACFS if you use some of the features below:
• Oracle RAC / RAC ONE NODE
• Oracle ACFS Snapshots
• Oracle ASM Dynamic Volume Manager
• Cluster Filesystem for regular files
ACFS Use Cases
• Shared Oracle DB home
• Other “file system” data
• External tables, data loads, data extracts
• BFILES and other data customer chooses not to store in db
• Log files (consolidates access)
• Test environments
• Copy back a previous snapshot after testing
• Backups
• Snapshot file system for point-intime backups
• General purpose local or cluster file system
• Leverage ASM manageability
Note : Oracle ACFS file systems cannot be used for an Oracle base directory or an Oracle grid infrastructure home that contains the software for Oracle Clusterware, Oracle ASM, Oracle ACFS, and Oracle ADVM components.
Regards,
Levi Pereira

Single node file system to 3 node rac and asm migration

hi,
we have several utl_file and external table applications running on 10.2 single node veritas file system. and we want to migrate to 3 node RAC ASM environment. what is the best practices in order to succeed this migration during this migration. thanks.

1. Patch to 10.2.0.3 or 10.2.0.4 if not already there.
2. Dump Veritas from any future consideration.
3. Build and validate the new RAC environment and then plug in your data using transportable tablespaces.
Do not expect the first part of step 3 to work perfectly the first time if you do not have experience building RAC clusters.
This means have appropriate hardware in place for perfecting your skills.
Be sure, too, that you are not trying to do this with blade or 1U servers. You need a minimum of 2U servers to be able
to plug in sufficient hardware to have redundant paths to storage and for cache fusion and public access (a minimum of 6 ports).
And don't let any network admin try to convince you that they can virtualize the network paths: They can not do so successfully
for RAC.

How to converrt files on RAW devices in ASM to non ASM file system.

Hi all,
I have on problem .
Is that possible to migrate ASM raw files system to non ASM file .
If possible plzz describe them.
If not also please tell y not?
Thanks in addvance
Regards
Krishna

Hi,
I totally agree with Mahir. And I just want to share one thing:
Use %U to generate guaranteed unique names :
For backupsets, %U means: %u_%p_%c
For an image copy of a datafile, %U means: data-D-%d_id-%I_TS-%N_FNO-%f_%u
For an image copy of an archived redolog, %U means: arch-D_%d-id-%I_S-%e_T-%h_A-%a_%u
For an image copy of a control file, %U means: cf-D_%d-id-%I_%u
Thank you

How to copy out ASM storege for archivelog to normal file system

Hi Expert,
I have two node running Oracle 11gr2 11.2.3 on SUN SOLARIS 64 bit. I need to copy out the archivelog store on ASM Flash recovery area to normal file system. How can i perform this task. How to ensure that after copy this archivelog can use for recovery.
Regard
William

Hi William,
Use this guide:
Step 4. Archived Online logs (archivelogs) and BackupSet stored in FRA
http://levipereira.wordpress.com/2011/09/16/how-migrate-asm-to-non-asm-unixlinux/
As you want copy, you must replace it:
this:
BACKUP AS COPY ARCHIVELOG ALL DELETE INPUT;
to:
BACKUP AS COPY ARCHIVELOG ALL;If you can still using FRA on ASM you can copy without change parameter "db_recovery_file_dest"
e.g
BACKUP AS COPY ARCHIVELOG ALL FORMAT '/u01/app/oracle/%U';
How to ensure that after copy this archivelog can use for recovery.Try it:
VALIDATE ARCHIVELOG ALL;
Regards,
Levi Pereira
Edited by: Levi Pereira on Jan 4, 2012 5:44 PM

Upgrade direct from 9i File System DB to 10g ASM instance

Can I upgrade from a 9i file system based instance directly to a 10g ASM based instance? without the middle step of a 10g file system instance.
Thanks
MN

The minimum compatibility for ASM storage system is 10.1.0, it is not possible to manage 9i instances in ASM, and there is no way to waive the 10g migration requirement.
If you are planning to use 10g ASM storage then you will have to migrate or upgrade your database to 10g first. Next you will have to move your datafiles, control and log files into the ASM storage.
0. Configure your +ASM instance
1. Upgrade to 10g (Upgrade procedure) or Migrate (exp from 9i/imp to 10g)
2. In case you upgraded then use RMAN as stated in the below given reference to move your datafiles to the ASM instance, or if you created the database in 10g make sure you defined +ASM as the default storage mechanism
Ref. Oracle® Database Backup and Recovery Advanced User's Guide
10g Release 2 (10.2)
Part Number B14191-03
Chapter 16.
http://download.oracle.com/docs/cd/B19306_01/backup.102/b14191/rcmasm.htm#i1016581
~ Madrid
http://hrivera99.blogspot.com

DNFS with ASM over dNFS with file system - advantages and disadvantages.

Hello Experts,
We are creating a 2-node RAC. There will be 3-4 DBs whose instances will be across these nodes.
For storage we have 2 options - dNFS with ASM and dNFS without ASM.
The advantages of ASM are well known --
1. Easier administration for DBA, as using this 'layer', we know the storage very well.
2. automatic re-balancing and dynamic reconfiguration.
3. Stripping and mirroring (though we are not using this option in our env, external redundancy is provided at storage level).
4. Less (or no) dependency on storage admin for DB file related tasks.
5. Oracle also recommends to use ASM rather than file system storage.
Advantages of DNFS(Direct Network File System) ---
1. Oracle bypasses the OS layer, directly connects to storage.
2. Better performance as user's data need not to be loaded in OS's kernel.
3. It load balances across multiple network interfaces in a similar fashion to how ASM operates in SAN environments.
Now if we combine these 2 options , how will be that configuration in terms of administration/manageability/performance/downtime in future in case of migration.
I have collected some points.
In favor of 'NOT' HAVING ASM--
1. ASM is an extra layer on top of storage so if using dNFS ,this layer should be removed as there are no performance benefits.
2. store the data in file system rather than ASM.
3. Stripping will be provided at storage level (not very much sure about this).
4. External redundancy is being used at storage level so its better to remove ASM.
points for 'HAVING' ASM with dNFS --
1. If we remove ASM then DBA has no or very less control over storage. He can't even see how much is the free space left as physical level.
2. Stripping option is there to gain performance benefits
3. Multiplexing has benefits over mirroring when it comes to recovery.
(e.g, suppose a database is created with only 1 controlfile as external mirroring is in place at storage level , and another database is created with 2 copies (multiplexed within Oracle level), and an rm command was issued to remove that file then definitely there will be a time difference between restoring the file back.)
4. Now familiar and comfortable with ASM.
I have checked MOS also but could not come to any conclusion, Oracle says --
"Please also note that ASM is not required for using Direct NFS and NAS. ASM can be used if customers feel that ASM functionality is a value-add in their environment. " ------How to configure ASM on top of dNFS disks in 11gR2 (Doc ID 1570073.1)
Kindly advise which one I should go with. I would love to go with ASM but If this turned out to be a wrong design in future, I want to make sure it is corrected in the first place itself.
Regards,
Hemant

I agree, having ASM on NFS is going to give little benefit whilst adding complexity. NAS will carrying out mirroring and stripping through hardware where as ASM using software.
I would recommend DNFS only if NFS performance isn't acceptable as DNFS introduce an additional layer with potential bugs! When I first used DNFS in 11gR1, I came across lots of bugs and worked with Oracle Support to have them all resolved. I recommend having read of this metalink note:
Required Diagnostic for Direct NFS Issues and Recommended Patches for 11.1.0.7 Version (Doc ID 840059.1)
Most of the fixes have been rolled into 11gR2 and I'm not sure what the state of play is on 12c.
Hope this helps
ZedDBA

File system to ASM Migration

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