NFS - What is it and why should we care?

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5 min read

NFS is the Network File System. It's been part of Linux and the broader Unix ecosystem for decades and been used for a long time in both enterprise environments to share files as well as in customized environments like high performance computing.

Jack Norris talks with Donnie Berkholz, PhD an analyst at RedMonk, about NFS in the context of Hadoop on the What Are The Facts video series. RedMonk is the first and only developer-focused industry analyst.

You can watch the video here:

Following is an excerpt from their conversation:

Jack Norris: With respect to Hadoop and NFS, what are the facts?

Donnie Berkholz: With Hadoop, the underlying file system, HDFS, is a write once file system. You're very limited in that you can't update files once they exist. You're either reading them or writing them. The problem that you run into is that there's no file close operation. You're unable to take the best kind of advantage of the file system you have available because you're writing and reading much more than you need to.

Jack Norris: Are there other approaches in the industry with respect to NFS?

Donnie Berkholz: Yes. There are absolutely other approaches. My understanding is that MapR has one of them.

Jack Norris: Well, it was a leading question Donnie, thank you for identifying that. No, in all seriousness, talk about the difference with NFS support if that underlying layer is a fully random read write storage layer.

Donnie Berkholz: One of the things we were talking about at the beginning of this segment is that NFS has been around for decades – behaving like an existing enterprise storage system that people who haven't used Hadoop are familiar with. This brings a lot of advantages in terms of familiarity and in terms of applications.

Jack Norris: Basically, it'll work out of the box, it'll support those applications. It'll behave like you expect it to behave.

Donnie Berkholz: Exactly. Without having to have some kind of customized connector or data ingestion engine and just be able to use the standard application rewrite using a POSIX format that's been around for decades. It makes things a lot easier for the developers trying to port it and creates a lot fewer issues by being able to use formats and protocols that are very well understood.

Jack Norris: How many applications support NFS?

Donnie Berkholz: All of them. I think pretty much every application ever written for Linux or for Unix understands how to write to a POSIX file system – NFS is one of those.

Jack Norris: POSIX file system – what exactly is that?

Donnie Berkholz: When I say POSIX, what I mean is, it uses a standard—that's existed for decades—of APIs, and of how to interact with the Unix system. It interoperates across any distribution of Linux or Unix.

Jack Norris: Excellent. I guess it's a good time now to point out, that's exactly how MapR works. Its NFS support is POSIX compliant. The next time someone says, "NFS and Hadoop," make sure you ask, "WATF?"

What Are the Facts is a series of short videos where we talk to industry analysts and examine claims and issues surrounding Hadoop. Other topics in the series include Snapshots and Disaster Recovery. Watch all the What Are The Facts videos on

In-line with its enterprise focus, MapR supports not just Hadoop interfaces but also industry standard interfaces including POSIX, NFS, LDAP, ODBC, REST and Kerberos to name a few.

For more details on the NFS advantage on the MapR Distribution for Hadoop, please click here for the Techbrief. Here is a quick video that showcases how to access Hadoop using your standard windows or mac browser.

This blog post was published June 18, 2014.