NFS Aliasing on Isilon

Question

IHAC that is migrating off NetApp to Isilon however they will need to maintain the same export paths from a workflow prospective. They have too many legacy applications, scripts, etc that have dependencies on the legacy paths. Trying to change the applications, etc would be too painful and hard to do. With their NetApp they used the export alias feature. Does anyone have ideas on how to achieve the same thing?

The partner we are working with suggested manually creating symlinks on nodes and export it. Initial testing seems to show it works but would it be supported?

example:

1. Create a symlink on the node in question: /data -> /ifs/data

· isilon-1# cd /; ln -s /ifs/data

2. Export the symlink

· isilon-1# isi nfs exports create /data

3. Mount the symlink from a host

· ubuntu# mkdir /data; mount –t nfs Isilon-1:/data /data

Verify browse and read

AndrewChung · Answer

Yes, this is supported.  It's ugly, but this works to keep old export paths in most cases.  I would suggest the customer start migrating away from the old paths to the new paths.

Peter_Sero · Answer

What's the point about the symlink?

ubuntu# mkdir /data; mount –t nfs Isilon-1:/ifs/whatever/else/might/be/in/the/way/data /data

will appear identically to the Ubuntu users when accessing files and dirs.

(mount and df will reveal the longer path on the server side, but that does not affect access.)

-- Peter

Peter_Sero · Answer

That must obviously be the case, thanks!

sfallon wrote:

> They have too many legacy applications, scripts, etc that have dependencies on the legacy path

This I all understand -- all application level --, but not being able to modify the fstab (system level)

was slightly beyond my imagination, until this point in time ;-)

-- Peter

AndrewChung · Answer

Peter,

The point is that they have clients which they cannot easily make a change to the mount table. So following your example, they have a mount like this in fstab:

OldServer:/root/path/to/nfs/export /data

They cannot/will not/or is prohibitively difficult to change it to say:

OldServer:/ifs/root/path/to/nfs/export /data

By using a symlink on the Isilon, they can just use a CNAME or other DNS trick to redirect clients from OldServer to Isilon-1. If you have thousands of clients, some that you may not have direct control over (different departments), you have issues to migrate over to an Isilon. Until Isilon gets NFS aliases (it's coming!) we have this issue.

cincystorage · Answer

I know it's not what we're talking about here,  but this also works for SMB access.

Peter_Sero · Answer

Either way, the number of distinct exports that would use the same linked path (such as isilon:/homes) is, err, limited... -- Peter

AndrewChung · Answer

It may work on SMB as well but I would not recommend using that at all.  There should be no reason to use that since SMB allows you to arbitrarily map a name to any place in the file system namespace.  NFSv3 does not allow you to do this in most implementations.

AndrewChung · Answer

Peter,

Definitely limited. We need to wait until NFS gets pulled into the access zones. When that happens you may be able to remap the NFS exports on an individual access zone basis. This will be another step toward full multi-tenancy.

dan-pncbank · Answer

i have  a problem deleting or modifying nfs alias on Isilon.  How can I get the root cause and fix for that issue?

Isilon

NFS Aliasing on Isilon

Was this post helpful?