Can we export one NFS share again through NFS server running on some other linux server

[senthil_kumar_1]

Hi All,

I have mounted some NFS shares in linux server coming from NetApp filer...

Now I would like to export the same share from this linux server to all other linux servers...

Is it possible?

[Alzhy · Accepted solution]

Bizarre --- I have not tried on Linux. I guess you can try.

Why not have the NetApp - being an excellent "Filer" do the NFS tasks? Is the reason more of a political than technical?

[Larry Klasmier]

I agree with Alzhy. Why would you want to do this? It seems to me that if this worked, and I am not sure it will, the data would need to travel across the network to the first linux server an then across the network again to filer. Doesn't seem efficient.

[Stephen P. Schaefer]

The short answer: it is not possible.

For at least nine years now, the Linux kernel has contained code to guarantee that directories which are NFS exported are "physically" present on the host providing the NFS service. "physically" present *can* mean that the disk is present via iSCSI or fibre channel or any number of other network layers, but that's at the block level, not the file system level. The kernel will refuse to export an NFS mounted directory.

About 14 years ago, the user-space NFS server implementation did allow this, but I only used it for a weird one-off situation for a couple days (definitely non-production).

I can imagine a number of use-cases where re-exporting an NFS mounted directory would be appropriate (I have a wild imagination), but it won't be easy to get it to work. Specifically, it appears that in recent kernels, fuse file systems may be NFS exported (http://lwn.net/Articles/281793/), so you may be able to put a fuse layer between the NFS mounted directory and the export. If you succeed, I'd love to hear about it.

[Viktor Balogh]

> I have mounted some NFS shares in linux server coming from NetApp filer...
> Now I would like to export the same share from this linux server to all other linux servers...

why not just modifying the netapp side to export the share to the "other linux servers"?

[macosta]

If you need to unify a namespace (all NFS exports coming from a single host IP), could you present block storage from the NetApp to the Linux host to use it as a local filesystem? You could then export that filesystem via NFS without issue.