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Sophia PaterakisFlag for United States of America

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Should I use automount nfs filesystems for Oracle datafiles?

I'm running some Oracle v11g databases on Solaris 10, and all of our datafiles are on nfs attached storage.  I would like to know:

Q: Should I use permanently mounted filesystems in /etc/vfstab, or automount filesystems in /etc/auto_direct

Both can be given the same parameters for hard mounting, transfer size, etc. but Oracle don't say one way or the other what is best.  Can anyone provide a white paper that gives some solid advice that's backed up with a rationale as opposed to simply a preference?
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slightwv (䄆 Netminder)

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If I had my choice I would not nfs mount file systems, however it does make for an easy way to add storage to a system.  You will see about 20% high CPU rates than a standard UFS file system, but the throughput is relatively close to what you could expect from standard spinning disks.  Of course there is direct attached SSD that standard UFS or NFS couldn't come close on. SSD would be my preferred database storage. However, if you are looking to save money and have CPU to spare then NFS is viable.  Here is a link to a white paper on the subject: http://www.cptech.com/stuff/contentmgr/files/0/f5e142f537d0b7b873e782e1d9603521/download/database_performance_with_nas_optimizing_oracle_on_nfs.pdf
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@slightvw

Yes, that's what I consider best-practice also... but my sysadmin and I have a difference of opinion, so I'd like something to help argue my case.


@achellstrom

Thanks for the advice, but we're locked into NFS at the moment.  We'll probably get SSD for the Redo logs during next years budget, but for now we're NFS only.

As for the PDF, under the section "NFS MOUNT OPTIONS", it says things such as:


The recommended mount options for Oracle9i RAC on Solaris are:  

rw,bg,vers=3,proto=tcp,hard,intr,rsize=32768,wsize=32768,forcedirectio,noac

... but nothing I can find mentions either setting them up in vfstab (permanently), or auto_direct (automount/dismount) <sigh>
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slightwv (䄆 Netminder)

Ah, debates.  Honestly anything we could likely provide would be from a Google search.

I suggest opening an SR with Oracle Support of contacting your Oracle Sales team for supporting evidence.


Who knows, it might not matter.
Thanks slightvw.  I actually raised an SR before I posted here, but I figured they would never deliver... just call me a cynic.

If they do pull a rabbit out of the hat, then I'll let you know... but I'd still like to hear from anyone else if you have the smallest sliver of backing documentation.
lol..  I feel your pain from the Support point of view.


Maybe I am just lucky but my sales team is fairly responsive to general questions.

Did you try them?

Never ever use automounting for Oracle database files.

Automounter is intended for filesystems that don't need to be mounted permanently, such as home directories, saving the trouble of manually mounting and saving server/client resources.

Oracle database filesystems always need to be mounted as the database is always online, so it makes no sense to automount these filesystems.

Using the automounter could potentially result in reliability issues that are difficult to trace back to the automounter.

Keep It Simple (KISS): something that isn't used can not cause problems.

Thanks robocat, and I agree that it's best practice not to use automount, and KISS as you mentioned.  What would really seal the deal for me is a document from Oracle, Sun, NetApp, or anyone of authority that confirms our collective opinion.
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Thanks everyone.  I leveraged the document that @robocat gave, to find this PDF:

NetApp Best Practice Guidelines for Oracle Database 11g
Oracle Alliance Engineering Team, NetApp
August 2011 | TR-3633

http://media.netapp.com/documents/tr-3633.pdf

It specifically relates to v11g, and was released only a few weeks ago so it's fresh advice.  Unfortunately the section on vfstab is copy/pasted directly from the previous document and makes no mention of automount:


Solaris NFS Protocol: Mount Options

For the latest NFS mount options and related information, see
http://kb.netapp.com/support/index?page=content&id=3010189.

Mount options are specified in /etc/vfstab for Oracle mounts that occur automatically at boot time. To specify mount options:

1. Edit the /etc/vfstab.
2. For each NFS mount participating in a high-spee

Oracle's advice on the subject was "Go and ask NetApp". :-)