Large files over nfs mount

[Barry Lowe]

I have a requirement to mount a filesystem using nfs. The native filesystem is on HP-UX and has 'large files' activated. The filesystem is then mounted via nfs on an AIX server which is using it to write an Oracle dump. The reason for this is that we do not have the required disk space on the AIX server.

The Oracle dump falls over when the file size reaches 2gig. Is there another setting in nfs/hp-ux/aix which needs to be triggered to allow the file size to exceed 2gig? Or does nfs simply not handle large files? I know I could specify a 2gig limit on the dump files as they are created but would prefer to have one big file and am curious to know if this can be done.

The OS versions are HP-UX 11.23 and AIX 5.3.

Thanks.

[Peter Godron]

Barry,
have you seen thread:
http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=72952
has some useful points such as NFS 3 level.
Have you tried to prealloc a 2GB+ file from the server side?
What tools are they using to write the dump from the client, as some of the tools may have a 2GB limit.

[Barry Lowe]

Thanks Peter.

I've run a couple of quick tests - I can use prealloc to create a 3gig file without a problem. I then used dd on the AIX server to create a 3gig file and it fell over after 2gig. This suggests an issue with either the OS or nfs - any ideas?

Cheers.

[Steven E. Protter]

Shalom Barry,

Note that nfs v3 or v4 can handle files bigger thatn 2 GB. Since largefiles is activated if the problem persists check AIX as the troublesome party.

SEP

[V. Nyga]

Hi,

fails the aix server to 'dd' at its own file system or at the nfs-mounted?
If it's the nfs-mounted - you have to set 'largefiles' in the mount command, too.

If it's at its own file system then you've an os problem you have to configure.

HTH
Volkmar

[Bill Hassell]

As mentioned, NFS is limited to 2Gb files *unless* both sides have enabled NFS version 3. Since the HP-UX is setup for largefiles, the AIX side needs help. You'll need to configure (install/upgrade?) NFS v3 or higher on the AIX side. On HP-UX, the nfsstat command will show version information from the AIX side.

[Dave Olker]

Hi Barry,

I don't think there is any "largefile" mount option for NFS, at least not on any version of NFS I've seen. I just checked my AIX 5.3 system and didn't see any mention of a largefile option.

So as long as the HP-UX filesystem has mounted the local filesystem with the largefile option and the client is mounting the filesystem with NFS v3 you should be able to access up to a 2TB file on an 11i v2 server.

Can you post the following command results from the AIX box:

# nfsstat -m

and the following command from the HP-UX system:

# mkfs -m

The nfsstat output should show conclusively which NFS protocol is used for the mount. The mkfs output should show whether the filesystem was built with the largefiles option.

Regards,

Dave

[Barry Lowe]

The dd/prealloc tests I ran were all done using the filesystem in question, mounted remotely and locally depending on which server.

Both sides are using NFSv3.

mkfs -m shows no largefiles option being used.

I've decided not to use largefiles now anyway as Oracle allows the user to specify a maximum size for individual dump files and there would be a performance overhead involved in using largefiles.

Thanks for you responses.

[Barry Lowe]

The dd/prealloc tests I ran were all done using the filesystem in question, mounted remotely and locally depending on which server.

Both sides are using NFSv3.

mkfs -m shows no largefiles option being used.

I've decided not to use largefiles now anyway as Oracle allows the user to specify a maximum size for individual dump files and there would be a performance overhead involved in using largefiles.

Thanks for your responses.

[Barry Lowe]

Closed as a workaround has been found