Re: Is nfs reliable?

Matt,

I respectfully disagree; there is indeed an easy answer.

First, the term "reliable" is ambiguous and must be clarified before engaging in a meaningful discussion. In this discussion, I believe the term "reliable" is not defined as the "absence of failure", but instead as "loss-less transmission of data", with "loss-less" meaning "complete and accurate".

TCP and UDP are alternative protocols residing at layer 4 (transport) of the 7-layer OSI model <https://en.wikipedia.org/wiki/OSI_model>. The first three layers of the OSI model define the hardware carrier, structure, framing, addressing, and routing of data, and it is at the transport layer that the branch between loss-less and loss-y session protocols is implemented.

NFS is implemented at level 7 (application) of the model, and so the question of "reliability" (as I believe we are discussing it) has been resolved several layers down.

In any context (analog, digital, or human), "reliable" never means "perfect". Error, loss, and corruption is always possible for a myriad of reasons, applying equally to any protocol. TCP is "loss-less" by design, but no design is absolutely perfect.

Hope this helps!

-Tim

On 6/3/16 13:17, Matt wrote:
>
> I do not think there is an easy answer whether or not nfs mounts are
> reliable. IT depends upon your organization infrastructe teams. I
> have worked at organizations were my nfs mounts were completely
> unreliable. My current organization I cannot remember the last time
> I have had an issue with my nfs mounts.
>
> Thanks, Matt
>
> *From:*oracle-l-bounce_at_freelists.org
> [mailto:oracle-l-bounce_at_freelists.org] *On Behalf Of *Robert Freeman
> *Sent:* Friday, June 3, 2016 1:31 PM
> *To:* Michael Cunningham
> *Cc:* oracle-l_at_freelists org
> *Subject:* RE: Is nfs reliable?
>
> I would not have an issue with monitoring scripts… However, anything
> diagnostic or the like I’d keep on local storage…
>
> *From:*Michael Cunningham [mailto:napacunningham_at_gmail.com]
> *Sent:* Friday, June 03, 2016 11:30 AM
> *To:* Robert Freeman <rfreeman_at_businessolver.com
> <mailto:rfreeman_at_businessolver.com>>
> *Cc:* oracle-l_at_freelists org <oracle-l_at_freelists.org
> <mailto:oracle-l_at_freelists.org>>
> *Subject:* Re: Is nfs reliable?
>
> Robert, how would you feel about having a library of monitoring
> scripts on an nfs mount? I do this so that scripts are available on
> every Oracle server. I also backup config files, etc. to this mount
> making it easy for me to scan, in a single directory, something like
> all cron backup files to see where something is running. It's these
> things why I feel the nfs mount serves a great benefit. And many others...
>
> Michael
>
> On Fri, Jun 3, 2016 at 8:34 AM, Robert Freeman
> <rfreeman_at_businessolver.com <mailto:rfreeman_at_businessolver.com>> wrote:
>
> Mike,
>
> We Run our RAC databases using NFS as the shared media for
> datafiles. We have yet to have a failure because of NFS. We don’t
> use shared software directories however, just local directories.
>
> My personal preference is for local software.
>
>
> RF
>
> *From:*oracle-l-bounce_at_freelists.org
> <mailto:oracle-l-bounce_at_freelists.org>
> [mailto:oracle-l-bounce_at_freelists.org
> <mailto:oracle-l-bounce_at_freelists.org>] *On Behalf Of *Michael
> Cunningham
> *Sent:* Friday, June 03, 2016 12:02 AM
> *To:* oracle-l_at_freelists org <oracle-l_at_freelists.org
> <mailto:oracle-l_at_freelists.org>>
> *Subject:* Is nfs reliable?
>
> I had someone tell me today that nfs should not be relied on and
> it should not be used for a shared mount that needed to be
> reliably available.
>
> Has anyone ever hear this before?
>
> --
>
> Michael Cunningham
>
>
>
> --
>
> Michael Cunningham
>

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