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multiple RAC on the same machines [message #210098] Tue, 19 December 2006 06:32 Go to next message
t1-oracle
Messages: 4
Registered: December 2006
Junior Member
Hi All,
I have a question about a RAC environment. I have 3 machines to use as a RAC. Also I want to install an ASM instance in these machines to use a common storage system.
My question is: can I install more than only 1 database instance in these machines?
I mean, I would install the ASM and also 2 database RAC instance in each machine to try to optimize the machine power.
I would experiment if the machines can support this configuration. Are there any studies in this way? Are there any documentation?

cheers
Federico Bonifazi
Re: multiple RAC on the same machines [message #210101 is a reply to message #210098] Tue, 19 December 2006 06:41 Go to previous messageGo to next message
Mahesh Rajendran
Messages: 10672
Registered: March 2002
Location: oracleDocoVille
Senior Member
Account Moderator
>> can I install more than only 1 database instance in these machines
Yes.
We use a Two Node RAC's.
Several databases are in RAC mode.
Few are Single instance mode regular databases using the local disk
and few also using the shared disk (but mounted on only in one Node or just a regular single instance database).

[Updated on: Tue, 19 December 2006 06:41]

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Re: multiple RAC on the same machines [message #210113 is a reply to message #210098] Tue, 19 December 2006 07:54 Go to previous messageGo to next message
t1-oracle
Messages: 4
Registered: December 2006
Junior Member
Hi Mahesh,
Thank for your help but I think I haven't correctly understood your situation. You told me you are using a RAC with more than only 1 database in running at the same time ?
In my mind there is a situation as this:
node 1 : (database 1 rac 1) + (database 2 rac 1)
node 2 : (database 1 rac 2) + (database 2 rac 2)
all at the same time

bye
Federico
Re: multiple RAC on the same machines [message #210138 is a reply to message #210113] Tue, 19 December 2006 09:54 Go to previous messageGo to next message
Mahesh Rajendran
Messages: 10672
Registered: March 2002
Location: oracleDocoVille
Senior Member
Account Moderator
Yes. You can have any number of RAC databases spread across different nodes as long as you have enough resources.
Same as you have multiple regular/single instance databases in
the same machine.


Re: multiple RAC on the same machines [message #212690 is a reply to message #210138] Sun, 07 January 2007 15:29 Go to previous messageGo to next message
oracle_scorpiongirl
Messages: 39
Registered: November 2005
Member
So, in my case, this is what I have right now for the 2 node development RAC DB on Linux x86 (32 bit), 4GB RAM
host1 - rac1
host2 - rac2
I am using asm (raw devices). So i have the clusterware, asm and the db installed and configured.

I want to create another DB (test environment) on the same hosts:
host1 - rac11
host2 - rac12

assuming that I have enough space, how do I design the components? Meaning.. my understanding is, I have to create some raw devices for OCR and Voting for the second database. I can use the same ASM diskgroups for data and flash recovery area (but will the disk groups be available for me to select in the installer?). and all i do is specify a different home for asm and the db. How about the RAM?

are there any 'gotchas' that I should be aware of?

I know I can just run the installer and find out the answer for most Q's I asked here. But I don't have access to the servers right now and I have to just walk-through a bunch of DBAs (with absolutely no RAC experience) to do this. I am a beginner myself. So, just want to understand the layout before I try for the first time in front of everyone.
Thanks much

Re: multiple RAC on the same machines [message #212767 is a reply to message #212690] Mon, 08 January 2007 04:17 Go to previous messageGo to next message
Mahesh Rajendran
Messages: 10672
Registered: March 2002
Location: oracleDocoVille
Senior Member
Account Moderator
>> I want to create another DB (test environment) on the same hosts:
Yes. But with different ORACLE_SID. rac1/rac2 are already been used.
You no need to create seperate voting disks etc for the second database.
Just invoke DBCA which will identify both the nodes. create new raw slices for second database
datafiles and ask DBCA to use it.
Re: multiple RAC on the same machines [message #213164 is a reply to message #212767] Tue, 09 January 2007 12:52 Go to previous messageGo to next message
oracle_scorpiongirl
Messages: 39
Registered: November 2005
Member
Thanks.

I am going to use the same clusterware and asm diskgroups for the test cluster (with different names than the development cluster).
Am I right here when I said same DATA and FLASH RECOVERY group for the second db? (I think so)

and invoke dbca and create the db.

how does entry in the /etc/hosts and oratab and everything else work. My understanding is.. once I create the second db, even crs_stat should show all resources on both db. but not sure about the other files. I think entries for the second db will be added to the oratab file. how abt /etc/hosts? (apologize if this is too basic to ask).

If you can explain it is great. or you can point me to any document or webpage that explains the 'internals' of how things work when I create a second db

and right now, I configured rman backups of the dev db to go to flash recovery area. (have a script for level0 and level1 backups). Now, if I login to the second db and run the rman script, it should backup just the files for the corresponding db to the flash recovery area. am i correct?
To me, should it be just like that one db on the server when I connect to one of the db/ (and everything else works just the same and fine) or should I change or add entries for the second db anywhere?
Thanks again
Re: multiple RAC on the same machines [message #213165 is a reply to message #213164] Tue, 09 January 2007 12:55 Go to previous messageGo to next message
oracle_scorpiongirl
Messages: 39
Registered: November 2005
Member
And one more thing about raw slices for the second db that you mentioned.
I thought I can use the same asm diskgroup for the second db. (I have space in the diskgroup for now) and may add more space to it when I have to.
is this thought process correct?
Re: multiple RAC on the same machines [message #213390 is a reply to message #213164] Wed, 10 January 2007 09:48 Go to previous message
oracle_scorpiongirl
Messages: 39
Registered: November 2005
Member
Please ignore my question about /etc/hosts, oratab and asm diskgroups. My bad. I understand now.
Created the database too.
Thanks Smile
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