NFS vs iSCSI – What’s the Difference? (Pros and Cons)

NFS vs iSCSI – What’s the Difference? (Pros and Cons). In this post, we are going to discuss the key differences between both protocols.

From the moment NFS and iSCSI became available for the virtual environment, they have remained the talk of the town. Users have often got confused about which one to run in their VMware environment.

Although it depends entirely on the environment and the type of data being used, it is essential to consider the cost, performance, availability,and ease of manageability before selecting any one of them.

Let’s start with NFS vs iSCSI – What’s the Difference? (Pros and Cons).

What is NFS?

Well to start with NFS or Network File System is a network protocol that enables you to share files stored on a disk or disk array of the server with other devices within a network.

It comes in versions that are detailed below:

  • NFSv3 – Every version is thoroughly improvised with enhancements. This version supports up to 64 bit file size, which means it can handle data or files larger than 2GB. Also it supports various writes on the server that prove to be effective in increasing the write performance. Further, it gives you support in high level authentications as well.
  • NFSv4 – This version is known for high performance enhancements and for providing prominent file security. Offers a protocol support for cluster deployments so that users can parallelly access files on different servers. Moreover, it uses GSS API to support high level authentication.

Features of NFS

Well it is vital to know what are the features that NFS provides its users:

  • Kerberization OptionNFS constitutes a kerberized file system interface. Hence, it provides additional Kerberos privacy that includes krb5p. This privacy is effective in providing its support to exciting Kerberos options like krb5 and krb5i.
  • Firewall FriendlyNFSv4 tends to use only one TCP port 2049 to run the services. This way, users can use the protocol across the firewall effortlessly.
  • Remote Procedural Call (RPC)Remote Procedural Call or RPC is available for both NFS and NFS client servers. It is capable of replacing the Transport Device Interface for better support and the best scalability.
  • Multiple Port Extensions – Supports RPC Ports that are not only firewall friendly but also effortlessly used by the client.
  • Mount Volume Point – With the help of Mount Volume Point, you can access vast mounted volumes under NFS 4.1 version.

Pros of NFS

The advantages provided by NFS are:

  • Firstly NFS is considered a matured protocol that enables users to appropriately understand the aspects of implementing, securing and using it.
  • Also considered a cost efficient network file sharing solution as it uses the existing network infrastructure.
  • Constitutes less movable media, which makes them more secure.
  • The centralized management in NFS mitigates the need for added software and disk space for individual user systems.
  • Users can also use NFS as a distributed file system. This way, they don’t have to look for removable media storage devices.
  • NFS ACL Support.
  • Benefit of large File Support.
  • Improvements in infrastructure led to assistance of Identity Mapping Windows PowerShell module.

Cons of NFS

Despite so many advantages, NFS has some limitations as well:

  • So with NFS it tends to become insecure due to its dependency and RPCs. Hence, it can only be used on a trusted network behind a firewall.
  • According to some reviews, the latest version of NFS has limited bandwidth and scalability. It also slows down during heavy network traffic.
  •  In nutshell sensitive to network congestion.

What is iSCSI?

iSCSI or Internet Small Computer Interface is a network protocol that creates interactions between objects in a network for sharing data. While an iSCSI initiator is configured from the client’s side, the target is configured from the server’s side.

Moreover, iSCSI is considered a session layer protocol as it operates on top of the TCP/IP stack. It shares all the data on a block level, which is also considered the key difference between NFS and iSCSI. Let’s move further to learn about the features provided by this protocol.

Features of iSCSI

Consequently iSCSI provides you with the following features:

  • Standard Ethernet – iSCSI utilizes standard ethernet that excludes the need of building exclusive components for the protocol.
  • IP Routing – As discussed above, iSCSI uses TCP/IP protocol that enables long distance IP routing to work without any external gateway hardware requirements. Also known for providing high flexibility and a vast storage network environment.
  • Storage Array – This protocol targets a vast storage array that is free from software based or commercial products. Different clients or users get unique iSCSI targets.
  • Security – iSCSI secures IP traffic in the network by authenticating and encrypting every data packet received in the networks.

Pros of iSCSI

More of iSCSI advantages to its users are:

  • Cost Efficient – When compared to NFS, iSCSI provides a less expensive connectivity network for transferring the files at the block level.
  • Leverage – Since it is an Internet based protocol, it leverages the interoperability benefits of TCP/IP and Ethernet.
  • Reusability – The user can use the existing server to configure the iSCSI implementation.
  • Reliable – Users don’t have to know the iSCSI storage system as it is very effortless to understand and configure.
  • Efficient – It is used for block storage as it is very fast.

Cons of iSCSI

  • Higher latency, which makes it arduous to guarantee the performance of mixed networks.
  • Although deploying this protocol is not very difficult due to software defined protocols, it needs the execution of other parameters while configuring initiators and targets.
  • It is susceptible to packet sniffing, a cyber attack users encounter while moving their data across a vulnerable network.

NFS vs iSCSI - Key Differences

NFS and iSCSI both are used for file sharing. However, both have some differences. Some of them are listed below.



Here with NFS is a file sharing protocol that is used for sharing data among multiple machines within the server. It allows you to mount a shared folder to the client machine.

The File system is handled in the NFS server itself.


On the other hand, iSCSI is a single channel architecture that shares data between the client and the server. Considered a block level based protocol.

The file system is taken care of by Guest OS in iSCSI.



In NFS, the cache is stored on an NFS server. A client machine consistently checks the metadata on the NFS server. In short, NFS uses client side caching. This will reduce the time taken for subsequent client access. In addition NFS also uses cache as a buffer memory for writing.


In the iSCSI, the caching policy is governed by the file system and the cache is stored on the client side. In general, asynchronous data update in iSCSI is less reliable than synchronous update used in NFS.



  • Read: blocksize: 16384KB Average: 908.8 Mb
  • Write: blocksize: 16384KB Average: 883.2 Mb
  • Write+Read blocksize: 16384KB Average: 435.2 Mb


  • Read: blocksize: 16384KB Average: 921.6 MB
  • Write: blocksize: 16384KB Average: 844.8 MB
  • Write+Read blocksize: 16384KB Average: 473.6 MB



Following NFS uses NIC teaming to protect shared data against network failures. If any one network interface fails, then another network interface can continue to work. In power failure conditions, NFS is more reliable than iSCSI.


But iSCSI uses the Storage Array Type plugin for failover implementation. In this case, you will need to map multiple iSCSI targets on different subnets to the iSCSI initiator. In the case of power failure, iSCSI a volume can be unrecoverable.



Furthermore NFS uses a host based authentication and its default configuration doesn’t provide encryption. However, you can use NFSv4 with Kerberos to enable the encryption and make the connection secure.

In NFS, you can define a single IP, multiple IP or entire subnet based access control to grant NFS access to client machines.


However in iSCSI, data traffic is not encrypted by default. You can define the user and password based authentication to access the share.
You can also use the Challenge Handshake Authentication Protocol (CHAP) to ensure that both the iSCSI server and client trust each other.

Thank you for reading NFS vs iSCSI – What’s the Difference? (Pros and Cons).

NFS vs iSCSI - What's the Difference? Conclusion

To sum up with this post  NFS vs iSCSI – What’s the Difference? we have explained key features, pros, cons and key differences between both NFS and iSCSI protocol. From the points discussed above, NFS proves to be much better than iSCSI. However, choosing one of them depends entirely on your needs, environment, and most importantly, your storage vendor. So, consider the difference before getting any one of them. 

NFS is considered to be a more efficient shared protocol as it can be implemented quite effortlessly. On the other hand, iSCSI requires the configuration of host parameters, making it arduous to handle and get implemented.

Finally with iSCSI the performance is slightly better but the drawback is the CPU load on the client host, which is higher as well as higher load on the network. Contrarily NFS is smoother and more predictable protocol.

Please take a look at more NFS content here.

Avatar for Hitesh Jethva
Hitesh Jethva

I am a fan of open source technology and have more than 10 years of experience working with Linux and Open Source technologies. I am one of the Linux technical writers for Cloud Infrastructure Services.

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