IS RAW DEVICES SUPPORTED OVER A CLUSTER FILE SYSTEM

Can raw partions be defined for datafiles after having choosen Cluster file system as storage option for database while creating fresh database using
DBCA?

> Do update on how the partitions have to be defined in either cases?
For both ASM and OCFS, a partition must exist on the disk - it can be of any partition type. Does not matter. Simply that the s/w references a partition and not an entire disk.
So for example, /dev/sdaf and dev/sdag are two shared devices on the cluster (LUNs on the SAN or whatever).
You create a partition on each. E.g
# fdisk -l /dev/sdaf
Disk /dev/sdaf: 36.5 GB, 36573020160 bytes
255 heads, 63 sectors/track, 4446 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Device Boot Start End Blocks Id System
/dev/sdaf1 1 4446 35712463+ 83 LinuxTo use the first device as a OCFS device, you need to build an ocfs file system on it using mkfs.
And then it can be mounted as a "normal" cooked file system mount. Remember that /etc/fstab needs to be updated for mounting it on startup.
To use the second device for ASM, you have two choices. If you have the ASMlib kernel module installed, you can use that to configure a volume label and assign it for use by ASM.
Alternatively, you simply map the device (partition) to a raw device for detection by ASM. E.g.
# raw /dev/raw/raw1 /dev/sdag1Of course, you also need to make this permanent by updating the raw device list config file so that this mapping is performed on reboot. On Linux, this is the /etc/sysconfig/rawdevices file. Also remember that the user and group access for the logical raw device created, must allow ASM full access to it (e.g. use chmod oracle.dba /dev/raw/raw1).
In a nutshell, this is how to raw devices are used as ocfs and asm volumes. (on RHEL specifically, but I expect no major differences in this approach on other o/s's)

Similar Messages

Raw devices versus Cluster File Systems in RAC 10gR2

Hi,
Does anyone using cluster file systems in a RAC 10gR2 installation, specifically IBMs GPFS?
Ive visited a company that is running RAC 10gR2 in AIX over raw devices. Why someone would choose to use raw devices , with all the problems to administer , when all the modern file systems are so powerful? Is there any issues when using cluster file systems + RAC? Is there considerable performance benefits when using raw devices with RAC ?
I´ve always used Oracle stand alone instances over file systems (since version 7) , and performance was always very good. I´ve tested raw devices almost 10 years ago , and even in that time (the hardware today is much better - SAN , 15K rpm disks , huge caches - and the file systems software today is much better) the cost to administer it does not compensate the benefits (only 5% more faster than file systems in Oracle 7).
So , besides any limitations imposed by RAC , why use raw devices nowadays ?
Regards,
Antonio Belloni

Hi,
spontaneously, my question would be: How did you eliminate the influence of the Linux File System Cache on ext3? OCFS2 is accessed with the o_direct flag - there will be no caching. The same holds true for RAW devices. This could have an influence on your test and I did not see a configuration step to avoid it.
What I saw, though, is "counter test": "I have tried comparing simple file copies from an OS level and the speed differences are not apparent - so the issue only manifests itself when the data is read via an oracle db." and I have no good answer to that one.
Maybe this paper has: http://www.oracle.com/technology/tech/linux/pdf/Linux-FS-Performance-Comparison.pdf - it's a bit older, but explains some of the interdependencies.
Last question: While you spent a lot of effort on proving that this one query is slower on OCFS2 or RAW than on ext3 for the initial read (that's why you flushed the buffer cache before each run), how realistic is this scenario when this system goes into production? I mean, how many times will this query be read completely from disk as opposed to use some block from the buffer? If you consider that, what impact does the "IO read time from disk" have on the overall performance of the system? If you do not isolate the test to just a read, how do writes compare?
Just some questions. Thanks.

Sun QFS cluster file system with Veritas Volume Manager

Hi,
Can someone confirm whether it is possible to create a Sun QFS cluster file system (for Oracle RAC datafiles) using a VxVM volume?
Or must we use Solaris Volume Manager with QFS?
Thinking of storing the static part of the Oracle RAC DB on VxVM raw devices, and the dynamic part on a QFS file system to avoid the overhead of constantly adding new raw devices when i want to create datafiles.
Thanks,
Steve

Steve,
No, shared QFS is only supported on Solaris Volume Manager. I've not heard of any plans to test it on VxVM.
Why not keep the static parts of the DB on raw SVM devices? Why keep them on raw devices at all?
Tim
---

Linux Cluster File System partitions for 10g RAC

Hi Friends,
I planned to install 2 Node Oracle 10g RAC on RHEL and I planned to use Linux File system itself for OCR,Voting Disk and datafiles (no OCFS2/RAW/ASM)
I am having SAN storage.
I would like to know how do i create shared/cluster partitions for OCR,Voting Disk and Datafiles (common storage on SAN).
Do i need to install any Linux cluster file system for creating these shared partitions (as we have sun cluster in solaris)?
If so let me know what versions are supported and provide the necessary Note / Link
Regards,
DB

Hi ,
Below link may be useful to you:
ORACLE-BASE - Oracle 10g RAC On Linux Using NFS

Linux Cluster File system

Has any seen a release date for oracle's linux cluster file system they announced last week. I am looking at deploying 3 4 node clusters over the next few months and would rather not use raw file systems.

http://www.linuxjournal.com/article.php?sid=6123&mode=thread&order=0
There is the link to the news release:

Best Practice for Distributed TREX NFS vs cluster file systems

Hi,
We are planning to implement a distributed TREX, using RedHat on X64, but we are wondering which could be the best practice or approach to configure the "file server" used on the TREX distributed environment. The guides mention file server, that seems to be another server connected to a SAN exporting or sharing the file systems required to be mounted in all the TREX systems (Master, Backup and Slaves), but we know that the BI accelerator uses OCFS2 (cluster file systems) to access the storage, in the case of RedHat we have GFS or even OCFS.
Basically we would like to know which is the best practice and how other companies are doing it, for a TREX distributed environment using either network file systems or cluster file systems.
Thanks in advance,
Zareh

I would like to add one more thing, in my previous comment I assumed that it is possible to use cluster file system on TREX because BI accelerator, but maybe that is not supported, it does not seem to be clear on the TREX guides.
That should be the initial question:
Aare cluster file system solutions supported on plain TREX implementation?
Thanks again,
Zareh

Asmca has grayed out Volumes and ASM Cluster File Systems 11.2.0.3

I've got a two node cluster which is up and running with the latest 11.2.0.3 grid install on Oracle Linux 6.3
I need to get a shared storage location I can use for File I/O testing, ASM looks like the solution with an ASM Cluster File System.
When I run asmca I do not have the ability to create these volumes or file systems as they are Grayed out.
I found some instructions on how to get it to work, and they said to use acfsload to start up the required daemons:
[root@oracleA bin]# ./acfsload start -s
ACFS-9459: ADVM/ACFS is not supported on this OS version: '2.6.39-300.17.3.el6uek.x86_64'
I installed Patches: 13146560, 14596051 - Which I thought would fix the problem. Rebooted after successfully applying the patches, but asmca still shows them greyed out
and not supported on this OS error persists.
I see some posts online saying to edit osds_acfslib.pm and update it to allow for the supported ORACLE version
Right now it shows: ($release =~ /^oraclelinux-release/))) # Oracle Linux
under /etc it only has oracle-release - could that have something to do with it not passing the check?
uname -r
2.6.39-300.17.3.el6uek.x86_64
From what I can tell this kernal should support asm..
Any help in getting these shared storage asm disks setup would be very helpful, oracleasm creates them and sees them fine for databases. Thanks.

Turns out the Kernel version 2.6.39 does not have support for the ASM Drivers for the ACFS mounting.
I'm going to have to use Oracle Linux 6.2 (instead of Oracle Linux 6.3) and rebuild my RAC to get a supported version of the drivers -> Kernel version 2.6.32
http://docs.oracle.com/cd/E11882_01/install.112/e16763/oraclerestart.htm#BGBGEDGA

WebLogic as Windows 2000 service over s shared file system

I am trying to install weblogic as a Windows 2000 service over a
shared file system with no sucess
(the shared fie system is provided by windows 2000 cluster services).
I am using the srvany utility to have the script that launches
weblogic be run as a service (I need this
because I must launch 2 instances of weblogic in the same machine
as services, i cannot do this
with the bea service tools, having different configurations for
the classpath, or can I?)
The service works if weblogic is not installed in a shared file
system.
On the shared file system, it fails (The service fails, is unabble
to start). I also made a script on the local file
system, that calls the weblogic script on the shared file system,
but weblogic fails to start (with no
message) when loading from the weblogic.classpath
thanks for your attenction,
Bruno Antunes
WhatEverSoft - Java Center

I have also tried running the service with the bea tools, with no
sucess when running in
the shared file system.
When i start the service, it seems to start ok, then stops. with
no message.
Nothing is written to the log, any ideas?
Bruno Antunes
WhatEverSoft - Java Center

Cluster file system and BDB - does it work ?

Hi,
I've read in the reference guide that:
" No commercial remote filesystem of which we're aware supports
coherent, distributed shared memory for remote-mounted files"
What about cluster file systems like veritas cluster file system ?
Can I use this file system with BDB ?
I'm trying to find a solution for having one database visible from two computers.
Reader and writer exist on each machine. Any clue how to do that ?
best regards
Moris

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Does /sapmnt need in cluster file system(SAP ECC 6.0 with oracle RAC)

We are going to be installing SAP with Oracle 10.2.0.4 RAC on Linux SuSE 10 and OCFS2. The Oracle RAC documentation states:
You must store the following components in the cluster file system when you use RAC
in the SAP environment:
- Oracle Clusterware (CRS) Home
- Oracle RDBMS Home
- SAP Home (also /sapmnt)
- Voting Disks
- OCR
- Database
What I want to ask is if I really need put SAP Home(also /sapmnt) on cluster file system? I will build a two nodes oracel 10g RAC and I also have another two nodes to install SAP CI and DI. My orginial think is sapmnt is a NFS share, and mount to all four nodes(RAC node and CI/DI), and all oracle stuff was on OCFS2(only two rac nodes are OCFS), anybody can tell me if SAP Home(also /sapmnt) can be NFS mount not OCFS2, thanks.
Best regards,
Peter

Hi Peter,
I don't think you need to keep /sapmnt in ocfs2 . Reason any file system need to be in cluster is,in RAC environment, data stored in the cache of one Oracle instance to be accessed by any other instance by transferring it across the private network and preserves data integrity and cache coherency by transmitting locking and other synchronization information across cluster nodes.
AS this applies to redo files, datafiles and control files only , you should be fine with nfs mount of /sapmnt sharing across and not having ocfs2.
-SV

Device id of the root file system changes

I have noticed that sometimes the device id of the root file system changes (it typically get incremented by one). This seems to happen after an abnormal shutdown. After a normal shutdown and reboot the device id reverts back to what it was previously.
/ is on a local disk (not NFS or anything like that) and I'm talking about the device id you can obtain via the following command:
stat / | cut -d' ' -f1
Any idea why this is happening?

boot up a (any) live CD, cp -a, generate a new grub.cfg/adjust menu.lst and don't forget to update your fstab - done.
Just done it myself.

RAC 10gr2 using ASM for RMAN a cluster file system or a Local directory

The environment is composed of a RAC with 2 nodes using ASM. I have to determine what design is better for Backup and Recovery with RMAN. The backups are going to be saved to disk only. The database is only transactional and small in size
I am not sure how to create a cluster file system or if it is better to use a local directory. What's the benefit of having a recovery catalog that is optional to the database?
I very much appreciate your advice and recommendation, Terry

Arf,
I am new to RAC. I analyzed Alejandro's script. He is main connection is to the first instance; then through sql*plus, he gets connected to the second instance. he exits the second instance and starts with RMAN backup to the database . Therefore the backup to the database is done from the first instance.
I do not see where he setenv again to change to the second instance to run RMAN to backup the second instance. It looks to me that the backup is only done to the first instance, but not to the second instance. I may be wrong, but I do not see the second instance backup.
Kindly, I request your assistance on the steps/connection to backup the second instance. Thank you so much!! Terry

Cannot configure Oracle Cluster File System (OCFS2)

Dears,,
While trying to use ocfs2console to Configure Oracle Cluster File System (OCFS2)
Error appear to me as following:
Could not start cluster stack error.This must be resolved before any OCFS2 filesystem can be mounted.
How can solve this please?
thanks & regards,,

Dear all ,,
My issue solved now . . .
Really , it is strange.
Once , i added /sbin in .bash_profile under ~ Directory as following . . .
export PATH=$ORACLE_HOME/bin:$ORA_CRS_HOME/bin:/bin:/usr/bin:/usr/sbin:/sbin:/usr/local/bin:/usr/X11R6/bin
Then log out then back again.
After this change , i able to run ocfs2console successfully.
Hope this help you.
Thanks for all,,
Best regards,,

Is OCFS(Oracle Cluster File System) a real file system?

Hi all
Is oracle cluster file system something kind of FAT23 or NTFS on Windows, ext3 on Linux ?
We install operating systems on FS , but with OCFS we install Oracle database on it instead of operation system ?
As usual
Applications
OS
File System
Physical Drive
But the ocfs is something like:
Oracle
OCFS
OS
OS's file system
Physical Drive
Is that right ?

Robert Geier wrote:
OCFS is a clustered filesystem. You don't use it for OS partitions (e.g /opt) but only for filesystems that will be shared between servers in a RAC cluster to hold database files.
Are you installing RAC ? If so, then ASM is a better option than OCFS. If not, then you really don't need OCFS.Thanks
I'm studying RAC.
I hear that I can not put all kind of files into ASM but with OCFS I can hold them.
Is that improved with 11g R2 ?

Cluster file system

i have 2 cluster nodes (SuSE Linux Enterprise server 9) with shared storage, i will install some applications on this storage(oracle is NOT one of these applications),
is the oracle cluster file system is suitable to use for this case?

only the ocfs2, and this is it first prodcution version, so it will be better for you to wait
for the next versions.

IS RAW DEVICES SUPPORTED OVER A CLUSTER FILE SYSTEM

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