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November 14, 2014 Previous day Next day

Transition of NFS to User Space in OneFS 7.2



In OneFS 7.2, EMC Isilon has transitioned NFS from Kernel Space to User Space.


As a result, you may notice some new naming conventions with the transition. The two key ones are:


kNFS - Kernel Space NFS (Pre-OneFS 7.2 NFS Protocol Server)

uNFS - User Space NFS (NFS Protocol Server introduced in OneFS 7.2)


In OneFS 7.2, uNFS required a significant re-write of the NFS protocol server. Although the NFS user experience is similar to past releases, uNFS now supports many of the enterprise features that were only previously available with SMB.  Consequently, you will notice a few changes to the CLI and Web Administration interface  to support uNFS.



NFS versions supported with uNFS are NFS v3 and NFS v4. NFS v2 has been deprecated and will no longer work in this OneFS 7.2.  This means that clients that do not support NFS v3 or v4 will no longer be able to access data stored on an EMC Isilon cluster.


uNFS also enables availability improvements for NFS, allowing EMC to patch uNFS without needing to reboot the entire node.  This was not possible with kNFS.


Goals/features of the transition to uNFS:

• Enterprise feature support (similar to SMB)

o Access Zones - Multi-tenant support for NFS

o Auditing - Security auditing for NFS

o NFS Aliases - Improvements for file server consolidations where pathnames cannot be changed for NFS clients.

o Availability - Ability to patch NFS without having to reboot the node


• NFS functionality improvements

o Multithreaded Mountd - Significantly improved performance for client mounts

o New nfsstat command - Provides more protocol details

o Exports now stored in gconfig - Faster performance and scalability

• Foundation for future performance and scalability improvements


Testing shows that uNFS performance is equivalent to kNFS performance, even with the transition of the protocol server to User Space.


In addition, the foundation is now set for performance increases over time with uNFS that would not have been possible with kNFS.



Web Administration and CLI modifications to support uNFS


Web Administration




New options have been added under "UNIX Sharing (NFS)" for selecting the access zone to assign an NFS export to, and for creating NFS aliases.



CLI Administration


New options for the isi nfs command are shown below:


Isilon1-4# isi nfs

aliases     exports     log-level   netgroup    nlm         settings


As of OneFS 7.2, you must specify the access zone when creating exports, and all output includes the access zone information:


Isilon1-4# isi nfs exports list

ID   Zone   Paths                    Description


6    System /ifs

7    System /ifs/.ifsvar/modules/fsa InsightIQ FSA - SYSTEM EXPORT

8    System /ifs/syncshare1          Syncplicity Vm NFS share for VM .247



Following is an example of listing exports specific to a specified zone, “zone-X”:


Isilon1-4# isi nfs exports list --zone=zone-X

ID   Zone   Paths         Description


9    zone-X /ifs/test/bob



In-depth details regarding new features, functionality, Web Administration changes, and CLI changes can be found in the OneFS 7.2 Documentation Info Hub in the following publications:


Isilon OneFS 7.2 Release Notes

Isilon OneFS 7.2 Web Administration Guide

Isilon OneFS 7.2 CLI Administration Guide

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