Difference between NFS and iSCSI

In today’s world, sharing of data is quite common. Basically, it is the process of sharing data or files written by an individual or a group of people and then it is available to multiple applications or websites and read by others. Both iSCSI and NFS are used for file sharing. However, both terms have some differences. They both provide different data-sharing semantics. Though for VM live migration, load balancing, and VM migration between datastores, both the implementations i.e, iSCSI and NFS can be used still there are many aspects on which they differ.

What is NFS?

NFS or Network File System is a kind of network protocol that allows the user to share files stored on a disk with other computers in the network. It was developed by SUN microsystems in 1984. It operates at the application layer of the Open Systems Interconnect (OSI) model. It shares data on the file level. While storing VM templates and ISO images for installing operating systems on virtual machines, NFS data stores are quite a good option and very convenient.

It has 2 versions available:

• NFS Version 2: It was the first version of the NFS protocol that is widely used. It is available on large numbers of platforms. The version of Solaris before 2.5 supports NFS version 2 only.
• NFS Version 3: With the release of Solaris 2.5, this new feature arises. There were several changes in terms of interoperability and performance. It can be run on both i.e, NFS servers and clients.

Key Features of NFS

• It has a kerberized file system interface, which provides privacy and further supports other Kerberos options. In short, it can be secured with firewalls and Kerberos.
• Users can use the protocol across the firewall easily.
• It supports RPC Ports. It can transfer files between computers running Windows and other non-Windows operating systems like Linux or UNIX.
• Remote Procedural Call or RPC is available which helps for better support and high scalability. 

Advantages of NFS

• It has large file support. Also, it has NFS ACL support.
• It is quite secure as it does not have movable media.
• It is quite easy to use and provides access to remote files.

Disadvantages of NFS

• It has various dependencies and RPCs, so it is quite insecure in that case.
• Some versions of NFS tends to slow down during heavy traffic network.

What is iSCSI?

iSCSI or Internet Small Computer Interface is a kind of network protocol that ensures the user the interaction of initiators and targets for sharing of data in the network. It can both be hardware and software-based. It was developed in 2003 but the first draft of the iSCSI standard was presented to the Internet Engineering Task Force (IETF) in 2000 by IBM. In iSCSI, data is shared on the block level. Basically, it is a transport layer protocol that should be transported over a TCP/IP network.

Key Features of iSCSI

• It uses TCP/IP Protocol which enables long-distance IP routing without the requirement of any external gateway hardware.
• It is used for securing IP traffic which is why it helps to establish and manage connections between the host and storage over IP.
• It has a large storage array. And, as it uses Block storage it is written fast and more efficiently than the other file transfer protocols.
• It does not require expensive components as it uses Standard Ethernet.

Advantages of iSCSI

• It supports multiple connections.
• It aims to communicate the stream between the client and the server.
• It is built on stable and familiar standards.

Disadvantages of iSCSI

• It has high latency.
• It is susceptible to packet sniffing.

Difference between NFS and iSCSI

Categories	NFS	iSCSI
Operating System	It is for both Windows and Linux Operating systems.	It is for Windows Operating System.
Usage	It is used to share data among multiple client machines.	It is used for sharing the data between single-channel architecture.
Sharing	It is having File-Based sharing.	It is having Block level-based sharing.
File System	The File system is placed at the server level and is handled by the NFS server itself.	The File system is placed at the client level and is taken care of by Guest OS.
Implementation	It is implemented easily because of its shared protocol nature.	It is difficult to handle and implement.
Storage	It holds more space as compared to iSCSI.	It holds less space when compared with NFS.
Caching	The cache is stored on an NFS server.	The cache is stored on the client side.
Reliability	NFS is more reliable than iSCSI, in power failure conditions.	It is less reliable than NFS.
Security	To make the connection strong, one can use NFSv4 with Kerberos to enable encryption.	Data traffic is not encrypted by default, so security is less as compared with NFS.

Which one to use between iSCSI and NFS, and why?

Though both iSCSI and NFS have their own features, pros, and cons, still the better option is to choose NFS over iSCSI. NFS works in an efficient manner, with all files whether it is small, medium, or large. Though iSCSI permits applications running on a single client machine to share remote data, it is not directly suitable for sharing data across machines. NFS is always the better choice in all categories. Depending on the user’s requirement, one can select which one to choose between them.

FAQs

Question 1: What are typical applications supported by iSCSI?

Answer:

Business applications, mission-critical applications, mail servers, databases, and eCommerce Applications. Basically, the applications that regularly access data are supported by iSCSI.

Question 2: What kinds of iSCSI products are currently on the market?

Answer:

There are numerous products that are available in the market such as hard disks, storage routers, storage switches, iSCSI initiators, and many more.

Question 3: What is iSCSI used for?

Answer:

iSCSI is an Internet Protocol based storage networking standard used for linking data storage facilities.

Question 4: Which one is the default port of the NFS server?

Answer:

It uses the 2049 TCP Port.

Question 5: NFS server version is checked by which command?

Answer:

‘nfsstat -o all’ is the command that shows all information about the versions that are active on the server.