Re: Shared APPL_TOP filesystem question

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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