Re: Shared APPL_TOP filesystem question
- From: Luis Freitas <lfreitas34@xxxxxxxxx>
- To: ora-apps-dba@xxxxxxxxxxxxx
- Date: Fri, 6 Nov 2009 10:43:42 -0800 (PST)
Chuck,
I don't agree that this setup can't deliver automated NFS failover.
It should be possible to set these boxes with a shared device, DRDB, OCSF2,
whatever, and use Oracle CRS to manage the NFS server and virtual IP.
The Linux NFS server already has some provisions to allow for a high
availability deployment. There are some parts missing, like proper nfs locks
replay, but it can be made to work as an application file system, where these
bits are not critical. Not sure on how this goes with other vendors, as they
would expect you to purchase their clusterware.
I am playing with a configuration like this here, with the added
complication of mixing Solaris clients with the Linux NFS server, over a OCFS2
filesystem. But we will purchase a NAS device next year so we may not need to
go into production with this setup. To ensure high availability we mounted the
filesystem using one of the RAC VIPs already setup on the server, since the NFS
server is also a RAC database server, and added some configuration parameters
on the NFS server to allow for a transparent reconnection on the client side.
But a NetApp filer provides a lot of functionality, like automated
snapshots, replication across remote or DR sites, etc.
Also we should not consider only the hardware cost, but the overal cost.
Implementing a solution like this with linux or Unix will need work from a
specialized O/S consultant, and also the post-implementation suport cost, for
which the filer could have better management tools. Depending on the size of
the deployment the suport costs offset the initial implementation cost.
Btw, you could install OpenFiler on those two boxes. I don't know if the
High Availability bits are on the community edition.
Best Regards,
Luis Freitas
--- On Fri, 11/6/09, Chuck Edwards <chuck@xxxxxxxxxxxxx> wrote:
> From: Chuck Edwards <chuck@xxxxxxxxxxxxx>
> Subject: Re: Shared APPL_TOP filesystem question
> To: ora-apps-dba@xxxxxxxxxxxxx
> Date: Friday, November 6, 2009, 4:03 PM
> From a performance requirement
> perspective, commercial NFS is overkill for shared
> application file systems. Standard Linux/UNIX NFS will
> do just fine and is quite cheap. For failover, you can
> simply set up two servers and have them rsync changes from
> one to another. If you experience a failure, simply
> mount the file system from the failover on your application
> servers and off you go. It's not instantaneous, to be
> sure, but it provides a couple of advantages:
>
> 1. Cost is very low. A pair of ~$900 white
> boxes with mirrored disk and 2 - 4GB of memory will do
> nicely.
> 2. Since you have two separate servers, you can place
> them in physically separate cabinets, an advantage that even
> expensive, internally-redundant NFS filers don't enjoy.
>
> Again, if instant, auto-magical failover for shared
> application file systems is an absolute requirement, this
> solution cannot deliver; however, performance would be just
> fine. ( If you take minimal steps to pre-configure mount
> points and /etc/fstab, then script up the mounting and
> dismounting, failover can be quite fast, though. )
>
> I suspect that with some of the new ASM capabilities in the
> 11.2 database release, we're going to see certification for
> shared application file systems in ASM, which will change
> this discussion substantially.
>
> Chuck Edwards
> chuck@xxxxxxxxxxxxx
>
>
> On Nov 6, 2009, at 9:48 AM, Luis Freitas wrote:
>
> > Hmmm,
> >
> > NFS thirdy party vendors are $$$, but
> operating system clusterware to manage NFS high availability
> can also be $$$.
> >
> > Sun cluster suite, HP cluster, or
> Veritas is not exactly cheap. I don't know how the
> clusterware licensing goes for AIX. For Redhat, RHCS used to
> be licensed separatelly but on the latest release they
> included it on the operating system license.
> >
> > Of course you can use Oracle CRS, but if
> the NFS servers doesn't have any other oracle products, you
> need to pay for a license too, and it won't be integrated
> with the O/S NFS server, so you can't expect any support
> from your OS vendor with the failover procedures that need
> to be implemented on CRS.
> >
> > Best Regards,
> > Luis Freitas
> >
>
>
>
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