Re: 10.2 NFS mount points
- From: Mladen Gogala <gogala@xxxxxxxxxxxxx>
- To: kevinc@xxxxxxxxxxxxx
- Date: Wed, 01 Feb 2006 06:46:47 -0500
On 02/01/2006 12:05:12 AM, Kevin Closson wrote:
>
> Mladen,
>
> The idea is to have a central NFS server for
> a bucnh of databases on a bunch of servers being
> backup up with RMAN...this isn't an argument over
> the virtues of DAS vs NAS.
Well, there is an error message, namely ora-27054 and two Metalink notes
338086.1 and 329942.1 which vaguely describe the so called "correct options".
The problem appears to be in the maximum read and write sizes for the file
system.
There aren't many 10.2 databases in production, especially not on AIX whose
owners
I find to be more conservative then the most, so he must break the ice. It will
take some experimenting and calling both IBM and Oracle support. The gentleman
has my sympathy and the advice to use hard drives if he doesn't feel like
doing that.
In connection to that, there is a new version of NFS protocol which
incorporates
some changes:
- allows local caching
- allows async I/O
- has improvements in the locking protocol.
Essentially, things that have been proprietary for vendors like NetApp are now
in the new protocol specification. That means that you will not only be able to
put RMAN backups on the NFS drive, you will be able to put data files there as
well. Red Hat FC3 has NFS4 client and here are the options, which are curiously
similar to those recommended by aforementioned Metalink papers:
Mount options for nfs4
Instead of a textual option string, parsed by the kernel, the nfs4
file system expects a binary argument of type struct nfs4_mount_data.
The program mount itself parses the following options of the form
'tag=value', and puts them in the structure mentioned: rsize=n,
wsize=n, timeo=n, retrans=n, acregmin=n, acregmax=n, acdirmin=n,
acdirmax=n, actimeo=n, retry=n, port=n, proto=n, clientaddr=n, sec=n.
The option addr=n is accepted but ignored. Also the following Boolean
options, possibly preceded by no are recognized: bg, fg, soft, hard,
intr, cto, ac, For details, see nfs(5).
Especially useful options include
rsize=32768,wsize=32768
This will make your NFS connection faster than with the default
buffer size of 4096.
hard The program accessing a file on a NFS mounted file system will
hang when the server crashes. The process cannot be interrupted
or killed unless you also specify intr. When the NFS server is
back online the program will continue undisturbed from where it
was. This is probably what you want.
This is, of course, taken from the manual page for "mount". Red Hat FC4 also
has NFS4
server, but it is compiled with GCC 4.0. Almost nothing else uses GCC 4.x at
this point,
so I'm waiting for FC5 to upgrade. What I'm really interested in is trying RAC
on
NFS4.
--
Mladen Gogala
http://www.mgogala.com
--
//www.freelists.org/webpage/oracle-l
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