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Is ASM a solution to a large recovery area [message #645023] Mon, 23 November 2015 21:20 Go to next message
juniordbanewbie
Messages: 217
Registered: April 2014
Senior Member
Dear all,

currently I have a system in which all the files are scattered across different filesystem/partitions,
from the OS, the mount point is as follow
[root@chicago-db ~]# df -h
Filesystem                         Size  Used Avail Use% Mounted on
/dev/mapper/rhel_chicago--db-root   22G  3.3G   19G  16% /
devtmpfs                            16G     0   16G   0% /dev
tmpfs                               16G     0   16G   0% /dev/shm
tmpfs                               16G   25M   16G   1% /run
tmpfs                               16G     0   16G   0% /sys/fs/cgroup
/dev/sdd                           355G  301G   36G  90% /u01
/dev/sdg                           355G  161G  176G  48% /u05
/dev/sde                           355G  303G   34G  91% /u02
/dev/sdb                           355G  303G   34G  90% /u04
/dev/sdf                           355G  309G   28G  92% /u03
/dev/sdh                           837G  483G  312G  61% /import2
/dev/sdc                          1008G   89M  957G   1% /import
/dev/sda1                          497M  120M  378M  24% /boot



from the db, the breakdown of database file size is as follow:

SYS@camden>SELECT substr(file_name,1,4), sum(bytes)/1024/1024/1024 size_in_g FROM dba_data_files GROUP BY ROLLUP(substr(file_name,1,4)) ORDER BY sum(bytes)/1024/1024/1024;

SUBS  SIZE_IN_G                                                                 
---- ----------                                                                 
/u05 40.2929688                                                                 
/u01 249.622993                                                                 
/u04 278.001892                                                                 
/u02 278.322205                                                                 
/u03 283.998962                                                                 
     1130.23902



conclusion recovery area for database should be about at least twice the size of current database file size which means recovery area should be about 2260 GB

if it is not possible to have a filesystem of 2260 GB, I guess the only solution is to have ASM
from http://docs.oracle.com/cd/E11882_01/server.112/e18951/asmcon.htm#OSTMG94059


Quote:

If you omit the failure group specification, then Oracle ASM automatically places each disk into its own failure group, except for disk groups containing disks on Oracle Exadata cells.

Normal redundancy disk groups require at least two failure groups. High redundancy disk groups require at least three failure groups. Disk groups with external redundancy do not use failure groups.


My interpretation of the above is as follow:

normal redundancy disk group can have 3 or even more disks because it state at least. so for external redundancy we can have as many disk as possible right?

So all I need to do is as follow

if each partition can only be 355G, about 7 disk 2260/355 are required, then I need to partition and configure the Disk Devices to Use the Oracle Automatic Storage Management Library Driver according to http://docs.oracle.com/cd/E11882_01/install.112/e47689/oraclerestart.htm#CHDFEDHB

install Oracle Grid Infrastructure for a Standalone Server 11.2.0.4 (Binaries for ASM) from p13390677_112040_Linux-x86-64_3of7.zip

Create the Diskgroup FRA


Migrate the existing flash recovery to FRA

Right?

Is there any other issues we have?

thanks and many thanks

[Updated on: Mon, 23 November 2015 22:11]

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Re: Is ASM a solution to a large recovery area [message #645024 is a reply to message #645023] Mon, 23 November 2015 23:09 Go to previous messageGo to next message
Mahesh Rajendran
Messages: 10690
Registered: March 2002
Location: oracleDocoVille
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>>if it is not possible to have a filesystem of 2260 GB
Why would it not be possible?
Behind all the glory, ASM is just a volume manager. You can treat it as you like it.
Unless you are planning to have FRA in local disks / Oracle Database Appliances (as opposed to SAN/Arrays which are already raided,
having dedicated controlllers etc and have decent Unix support to maintain them),
You can just use external redundancy.
If you are planning to use ASM for FRA, migrate the database as well into ASM.
Else, it would be an overkill.




[Updated on: Mon, 23 November 2015 23:20]

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Re: Is ASM a solution to a large recovery area [message #645026 is a reply to message #645024] Tue, 24 November 2015 00:06 Go to previous messageGo to next message
juniordbanewbie
Messages: 217
Registered: April 2014
Senior Member
>>if it is not possible to have a filesystem of 2260 GB
Why would it not be possible?
>>>when I suggest this size my supervisor seems to be surprise by it
>>>if all they can provide is 355 GB, then of course ASM is the solution.

If you are planning to use ASM for FRA, migrate the database as well into ASM.
Else, it would be an overkill.

=>don't get what you mean, are you saying that if fast recovery area is using ASM and Database using filesystem, it would be overkill, why is it overkill?

thanks
Re: Is ASM a solution to a large recovery area [message #645031 is a reply to message #645023] Tue, 24 November 2015 01:02 Go to previous messageGo to next message
John Watson
Messages: 7619
Registered: January 2010
Location: Global Village
Senior Member
You should put the database on an ASM diskgroup too.

Also, you should use GI release 12.1.0.2, not 11.2.0.4 (which is already in extended support).
Re: Is ASM a solution to a large recovery area [message #645032 is a reply to message #645023] Tue, 24 November 2015 01:08 Go to previous messageGo to next message
John Watson
Messages: 7619
Registered: January 2010
Location: Global Village
Senior Member
One more point -
Quote:
I need to partition and configure the Disk Devices to Use the Oracle Automatic Storage Management Library Driver

This is not a good idea. The ASMLib is history, replaced in 12.1.0.2 with the ASM Filter Driver. However, the FIlter Driver is (I think) not yet ready for production use. I would advise that you use ether at the moment, but rater use udev to configure the devie ownership and modes. udev is easy and reliable and your system administrators love it.
Re: Is ASM a solution to a large recovery area [message #645033 is a reply to message #645032] Tue, 24 November 2015 01:27 Go to previous messageGo to next message
juniordbanewbie
Messages: 217
Registered: April 2014
Senior Member
I would advise that you use ether at the moment, but rater use udev to configure the devie ownership and modes. udev is easy and reliable and your system administrators love it.
=>I supposed what u mean is used neither at the moment
rather use udev to configure the device ownership and modes

but in the future I believe if we want to use asm filter driver, we cannot use udev right? i can't change udev to filter driver https://docs.oracle.com/database/121/OSTMG/GUID-ECAFF45E-CB7F-4C43-B8E2-7F6DBA77F964.htm

and many thanks

Re: Is ASM a solution to a large recovery area [message #645034 is a reply to message #645033] Tue, 24 November 2015 01:51 Go to previous messageGo to next message
John Watson
Messages: 7619
Registered: January 2010
Location: Global Village
Senior Member
At the moment, the only way to install the Filter Driver is to install ASMLib first. Which is stupid. I am sure beyond all reasonable doubt that this will be fixed in a future release. Which is why I would use neither now, and stay with udev.
Re: Is ASM a solution to a large recovery area [message #645041 is a reply to message #645026] Tue, 24 November 2015 05:53 Go to previous message
Mahesh Rajendran
Messages: 10690
Registered: March 2002
Location: oracleDocoVille
Senior Member
Account Moderator
>> why is it overkill?
Because ASM is just a volume manager, with certain special implementation tailored to be used by an Oracle database.
Why would you go through all the pain (setting up and maintaining the Grid) and use it just as filesystem for FRA?
FRA can happily reside outside, just like a conventional file system.
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