Re: RAC & Linux

Hope, Jim, Group,

OCFS is ok, but has its limitations : see metalink or OTN OCFS will only hold control-, data-, redo- arch- and spfile. It will explicitly NOT hold other files.

If you want other files (like oracle_home, or ETL) files to be shared, you need another CFS or go for some NFS-type shared mountpoints.

It is my Strong Opinion that you should not start a cluster of more then 2 nodes without a CFS that stores all files, notably Ora-home. Dispersing ora-home over >2 nodes is too much work and too much risk, at least in 9i.
Note: OUI will only handle up to 8 nodes, and I do not approve of its copy-strategy: it is not good practice to store+maintain multiple versions, other then for reasons of deliberate saftey/redundancy. The ease of management in a single ora-home, compared to multiple copies is compelling: try it.

The presentation you saw at OOW was by Kevin Closson, Polyserve, and his whitepaper is well worth reading, allthough he will strongly promote his
product too, can't blame him.

Basically, your requirement should be: a clustered file system that can hold ALL files, no limits.
On linux, you may have to compromise, like we did: placed the database on OCFS, and all other files on an NFS device.

Kevin may or may not forgive me that I mention some other CFS-es:

• OpenGFS : not usable for oracle yet, but might be getting there.
• Sistina (need entreprise-version avoid single-point of faillure)
• Veritas (not for Linux yet, announced, I think)
• TrueCluster, Tru64 : proprietary, expensive, old, but very usable.
• GPFS : proprietary, comes with AIX

NB: Just Dreaming: Get bunch of KNs (Knowledgable Nerds) together and hammer out the UCFS: Ultimate Clustered File System, maybe under the OpenSSI initiative ?
Most of the knowledge is already out there: OCFS and OpenGFS are open-source, and openssi.org has interesting stuff available. This would of course kick some vendors in revenue-spots, so sponsorship would be difficult.
If only I was a true nerd....

Regards,

PdV

"Jim Kennedy" <kennedy-down_with_spammers_at_no_spam.comcast.net> wrote in message news:<1AE9b.365702$Oz4.143642_at_rwcrnsc54>...
> "utkanbir" <hopehope_123_at_yahoo.com> wrote in message
> news:f6c90ebe.0309160340.4fe970da_at_posting.google.com...
> > Hi Gurus ,
> >
> > I have a question about Oracle Real Application Clusters . My system
> > is Linux - Itanium , EMC , oracle 9x . This is a datawarehouse system
> > . Our data files are stored by using Oracle clustered file system on
> > EMC disk array.
> > In order to extract and load data from source system to datawarehouse
> > system , i use external tables. Basically , i load data by using
> > external tables . My problem is with the locations of external files.
> > At first i used oracle clustered file system but strange things
> > happened there . ( tried to edit file or scripts by using vi , when i
> > save the file , the contents are lost!!!)
> >
> > If i use a file system on one of the hosts , the other one cant see
> > the external tables since the files are not stored in a clustered file
> > system but regular file system. How can solve this problem apart from
> > copying all data from one host to another? (One solution may be to
> > have an ability which allows me to force RAC to use only one server
> > for my external tables , is there such a method?)
> >
> >
> >
> > Kind Regards,
> > hope
> At Oracle World I went to a presentation where they talked about this. It
> was on a 16 node RAC cluster set up. The guy was emphatic that you needed
> shared area for things so you could have 1 shared Oracle home (not do 16
> installs) and same for archive logs and external tables. If you have a
> shared area then external tables work very well. You can do parallel query
> on them across nodes for data warehouse etl loads. For that reason they
> used a file system from Polyserve (I think).
> Jim
Received on Wed Sep 17 2003 - 03:29:15 CDT