Shared Disks For RAC

Hi,
I plan to use shared disks to create Oracle RAC using ASM. What options do I have? OCFS2? or any other option?
Can some one lead me to a documnet on how can I use the shared disks for RAC?
Thanks.

javed555 wrote:
I plan to use shared disks to create Oracle RAC using ASM. What options do I have? You have two options:
1. Create shared virtual, i.e. file-backed disks. These files will be stored in /OVS/sharedDisk/ and made available to each guest
2. Expose physical devices directly to each guest, e.g. an LVM partition or a multipath LUN.
With both options, the disks show up as devices in the guests and you would then provision them with ASM, exactly the same way as if your RAC nodes were physical.
OCFS2 or NFS are required to create shared storage for Oracle VM Servers. This is to ensure the /OVS mount point is shared between multiple Oracle VM Servers.

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VMWare Fusion & Shared Disks for RAC install

Does anyone have any advice on how best to install a 2 node RAC 10G on a Macbook Pro. I've searched the forums here and haven't found much on this subject.
I'm having problems setting up the shared disks to be used for the voting disk and ASM.
Cheers,
Mike

This link might help you in what you are looking for.
http://www.apple.com/itpro/profiles/rotech/
Good luck,
--MM

Doubts about shared disk for RAC

Hi All,
I am really new to RAC.Even after reading various documents,I still have many doubts regarding shared storage and file systems needed for RAC.
1.Clusterware has to be installed on a shared file system like OCFS2.Which type of hard drive is required to install OCFS2 so that it can be accessed from all nodes??
It has to be an external hard drive???Or we can use any simple hard disk for shared storage??
If we use external hard drive then does it need to be connected to a seperate server alltogether or can it be connected to any one of the nodes in the cluster???
Apart from this shared drives,approximately what size of hard disk is required for all nodes(for just a testing environment).
Sincerely appreciate a reply!!
Thanks in advance.

Clusterware has to be installed on shared storage. RAC also requires shared storage for the database.
Shared storage can be managed via many methods.
1. Some sites using Linux or UNIX-based OSes choose to use RAW disk devices. This method is not frequently used due to the unpleasant management overhead and long-term manageability for RAW devices.
2. Many sites use cluster filesystems. On Linux and Windows, Oracle offers OCFS2 as one (free) cluster filesystem. Other vendors also offer add-on products for some OSes that provide supported cluster filesystems (like GFS, GPFS, VxFS, and others). Supported cluster filesystems may be used for Clusterware files (OCR and voting disks) as well as database files. Check Metalink for a list of supported cluster filesystems.
3. ASM can be used to manage shared storage used for database files. Unfortunately, due to architecture decisions made by Oracle, ASM cannot currently be used for Clusterware files (OCR and voting disks). It is relatively common to see ASM used for DB files and either RAW or a cluster filesystem used for Clusterware files. In other words, ASM and cluster filesystems and RAW are not mutually exclusive.
As for hardware--I have not seen any hardware capable of easily connecting multiple servers to internal storage. So, shared storage is always (in my experience) housed externally. You can find some articles on OTN and other sites (search Google for them) that use firewire drives or a third computer running openfiler to provide the shared storage in test environments. In production environments, SAN devices are commonly employed to provide concurrent access to storage from multiple servers.
Hope this helps!
Message was edited by:
Dan_Norris

OVM disks for RAC implementation

Dear All
is there any guide available on how can you create the disks for RAC ASM in OVM 3.3.1 using a fiber channel block level storage?
Thanks
George

You are right, you can't use virtual disks for RAC configuration. Have a look here (especially page 18):
http://www.oracle.com/technetwork/products/clustering/oracle-rac-in-oracle-vm-environment-131948.pdf
Using physical disks means that you create LUNs on your storage array connected to Oracle VM Servers by fabric channel. You map these LUNs to all servers in the pool or all standalone servers where you are going to install your virtual machines being Clusterware nodes. Then you rediscover storage in Oracle VM Manager, mark these LUNs as "shared" in OVMM and add them to your virtual machines as "Physical disks" (by editing guest properties in OVMM).
Alternatively you can directly map iSCSI or NFS storage to your guests. By "directly" I mean you use IP addresses and software in your guests as iSCSI initiator or NFS client - without engaging Oracle VM in the middle.
Regards,
Michal

How Prepare Disks for RAC installation

How configure disks for RAC instalation for Windows Enterprise Server 2003

Best resource for RAC on Windows:
www.jobcestbon.com/oracle/RacOnWindows.pdf
HTH
Thanks
-Chandra PabbaI read it, but i unable to configure Shared Memory accourding to this link. Please guide me how i can configure shared Memory for RAC in Windows Server Enterprise 2003.
Thanks

Shared Storage for RAC

Dear All,
what is the best options for shared storage system for Oracle RAC 10g R2 on windows operating system.
How to share disk in windows so that it can be available in all RAC nodes in Dynamic mode.
Need help from people who have configured RAC on windows operating system and have used shared disk option.
Regards,
Imran

In production, the only realistic options are to turn to certified SAN or NAS vendors.
The issue is simplel - even though many types of shared storage allows you to have multiple machines connected to the same disk, certified shared storage allows these machines to write to the same disk sector and block. Most storage solutions have built-in protection to stop that from happening.
For a small shop, I certainly recommend NetApp NAS.

Which external disk for RAC at home?

Dear Experts,
Years ago, I tried installing RAC at home on Linux 2.1.
With 2 Dell machines and a firewire external disk.
I was only partially successful.
Today, with Oracle 11, what would be a good external harddisk
to use? A small external NAS, or SAN through the router,
with Oracle Clusterware? Something else?
Multiple VMs with a single internal disk?
This detail is important!
Thanks a lot!

You can go the external shared disk route or you can even go the nfs mounts way. Here is the virtualization route:
http://www.oracle-base.com/articles/10g/OracleDB10gR2RACInstallationOnCentos4UsingVMware.php
Perhaps virtualization is the cost effective way (although it is no where the production grade)
Good Luck

WFC without Shared Disks for SCVMM Failover

SCVMM Failover Cluster requires us to first have a WFC in place. If shared disk is the limitation, can a WFC be created without shared disks? just to fulfill the purpose of providing WFC to the SCVMM Failover Cluster.

Thanks for the reply. Actually, design is not my decision unfortunately.
I have gone ahead with a disk witness and I have used Shared VHDX as a Quorum Disk. I faced some issues when I live migrated, but when I enabled Guest Services on both nodes which is disabled by default, it started migrating fine.
Please, do share your thoughts on it. Especially with respect to Shared VHDX and Live migration and the overall strategy as MS always prefers Disk Witness to File Share Witness.

Redo log groups/files on the local disk for RAC DB

Whether is it possible/supported to place redo log files/groups on the local disk for a RAC databases ?
Thank you,

Hi Mufalani,
are you sure about this one? I'd think that this only works as long as the nodes don't restart/crash. I can imagine this like this:
The nodes store redo logs on local disks which are NFS-exported to the other node. Everything should be fine. But when one node crashes/reboots, the other one has to perform crash recovery for the crashed instance but this won't work when the NFS mount (with redo logs) is unaccessible. So I would not want to do this.
Bjoern

Shared disks for clusterware

Hi:
I am setting up Oracle Clusterware. I am trying to set it up on two nodes. This i on AIX and trying the latest version 11gR2. I am selecting the first option ( Install and Configure Grid Infrastructure for a Cluster)
I am trying to setup shared disk by mounting a file system of one system on the other using NFS.
Here are my questions.
I am creating user "oracle" on both the boxes. I am adding all the groups (like dba, oinstall etc.)
Here are my questions:
The NFS mount I have which is accessible by both the boxes should be used only for OCR (Oracle Cluster Registry) and Voting Disk (CF). I do not have ASM.
Is it correct?
Also
The Oracle Base(eg : /u01/app/grid ) and Software Location(eg : /u01/app/11.2.0/grid) can be local to each individual nodes
Is it correct?
Those are the two questions I have. Also, will this work?
I have tried to put everything on the shared disk (installation files, OCR, CF, base, inventory etc) but looks like the second box (the one from where I have not installed) is having problem. Because it is trying to change ownership of user and group of a few files when I run orainstRoot.sh and root.sh.
Please let me know
Thanks

Hi,
The NFS mount I have which is accessible by both the boxes should be used only for OCR (Oracle Cluster Registry) and Voting Disk (CF). I do not have ASM.
Is it correct?Use documentation of Oracle GI 11.2
http://docs.oracle.com/cd/E11882_01/install.112/e24614/storage.htm#CDEJIDFB
Why not use ASM? Since is more safe and have more performance.
Also
The Oracle Base(eg : /u01/app/grid ) and Software Location(eg : /u01/app/11.2.0/grid) can be local to each individual nodes
Is it correct?
Those are the two questions I have. Also, will this work?For grid infrastructure for a cluster installations, the Grid home must not be placed under one of the Oracle base directories, or under Oracle home directories of Oracle Database installation owners, or in the home directory of an installation owner. During installation, ownership of the path to the Grid home is changed to root. This change causes permission errors for other installations.
http://docs.oracle.com/cd/E11882_01/install.112/e24614/preaix.htm#BABFCFIH
Please follow the installation guide, all your question here is easily answered on documentation:
http://docs.oracle.com/cd/E11882_01/install.112/e24614/preaix.htm
Regards,
Levi Pereira

Setting up a shared disk for Time Machine

Folks,
I have a 24" Al iMac with an external 750GB disk allocated to time machine.
This machine has a single account with administrative privileges "me".
I have a second 20" snow iMac that I would like to backup to the same disk.
It has 4 accounts, one of which has administrative privileges (also called "me").
How do I need to configure sharing on the Al iMac to allow time machine on the snow iMac to see the drive on the Al iMac, and be able to backup/restore to this volume?
I have searched the forums here but cannot seem to find this information.
Thanks in advance.
- ljm

Turn on Filesharing in the "Sharing" preference pane on both computers (You might want to specify which users have access via filesharing). Then on the snow imac connect to your Aluminum imac and mount the external drive so you can access it. Go to the TM settings and select the Aluminum imac's drive that's now shared and mounted, and start the initial backup. It will create a "sparsebundle" disk image on the backup drive and use that for the snow imac's backup. Everytime it writes to the image, it will mount it over the network and do a backup, and then eject it. Sometimes it wont back up to the image if you're not connected to the Aluminum mac, so to solve this, select the mounted shared drive as a "login item" in the snow imac's user preferences (for each user). This will create the connection on login, and backups should proceed accordingly.
Message was edited by: Topher Kessler

Keep Sequences in Shared Pool for RAC Environment

Hi,
We have 2 node RAC setup for production environment. I want to pin cached sequences in my database. We are using following command for this purpose.
EXEC DBMS_SHARED_POOL.KEEP('HR.MySeq','Q');
Do I need to execute this command for each single node?

Pinning is in the Shared Pool in the SGA. So it is local to an instance.
Therefore, you would need to execute it in each instance (i.e. on each node).
Note : However, with sequences in RAC, you have to be careful with the definition. Have you defined it or do you need to define it as CACHE/NOCACHE ? Have you defined it or do you need to define it as ORDER (to guarantee order generation in RAC) ?
Hemant K Chitale

How to pin sequences in the shared pool for RAC?

We have a RAC environment with two instances. I want to pin some sequences in the shared pool to boost the performance. Do I need to pin them in both of the instances or just pin them in one instance?
Thanks in advance

If you cannot tolerate gaps, you must not use sequences. Period. A sequence-generated key will have gaps because transactions roll back, because databases get shut down, etc. If you want to ensure that there are no gaps, you have to write code that serializes access to a resource (i.e. a custom table of sequences) over the full length of a transaction. Of course, this is hugely inefficient and kills the application's scalability, but it does prevent gaps. Sequences are much faster and much more scalable, but they do not and can not guarantee that there are no gaps.
Assuming the intention is to minimize gaps, rather than to eliminate them, NOCACHE & ORDER can help. That means, though, that you may need to communicate with the other nodes in the cluster every time you need a new value from the sequence, which is the slow part. Pinning the sequence is not going to be beneficial.
Justin

OCR and VOTING DISK for RAC Database on ASMLib env

Can i use raw device for OCR and Voting Disk while installing Clusterware, i am planning to use ASM with ASMlib,
i know i can configure asm with dbca when i am using raw devices (to be user for ASM), How i can configure diskgroups when i use ASMlib, Can i configure ASM diskgroup with dbca , if yes plz forward me some metalink notes to study or any other help.

Hi,
Can i use raw device for OCR and Voting Disk while installing ClusterwareYes:
http://www.oracle.com/technology/pub/notes/technote_singh_crs.html
"Step 3: Create Raw Devices for the OCR and Voting Disk Before we start the installation"
plz forward me some metalink notes to study or any other help. I like Madhu Tumma's examples with raw devices because it has step-by-step examples:
http://www.rampant-books.com/book_2004_1_10g_grid.htm
Hope this helps . . .
Donald K. Burleson
http://www.dba-oracle.com

CRS and Voting Disk for RAC

Hi Friends,
How much disk space size should be allocated for CRS and Voting Disk?
Thanks a lot

Hi,
Is it ok if i put them into one LUN ? say /u02 200M under it are directory CRS and Voting, or it is
better to separate them into two LUNS /u02 /u03.
Thanks a lot

Shared Disks For RAC

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