Difference between ZFS and UFS

The file systems ZFS (Zettabyte File System) and UFS (Unix File System) are both used in Unix-based operating systems. While both have been designed to manage and store data, they have numerous fundamental differences.

ZFS is a modern file system that prioritizes data integrity and provides better levels of data protection and security through features such as checksumming, snapshots, and RAID-Z. UFS is an older file system developed in the early days of Unix that lacks some of ZFS's advanced features and scalability.

Read this article to find out more about ZFS and UFS and how they are different from each other.

What is ZFS?

ZFS is a modern file system that prioritises data integrity and provides better levels of data protection and security through features such as checksumming, snapshots, and RAID-Z.

Data integrity is one of ZFS's most critical features. It uses a checksum system to validate the integrity of any data written to the file system. If it identifies a mistake, it can automatically repair the corrupted data by using redundant copies of the data stored on the disc. This feature protects data against corruption caused by hardware failures, data transport issues, and other factors.

ZFS also has advanced storage management features, like the ability to create and manage storage pools. Storage pools are collections of storage devices that can be dynamically assigned and resized as needed without the need for downtime or extensive configuration. This makes managing massive data collections and scaling storage resources simple.

ZFS also has data integrity features such as checksumming, which assures the integrity of data stored on disc. A checksum is calculated and stored with the data when it is written to disc. The checksum is recalculated and compared to the stored checksum when the data is read back to ensure that it has not been corrupted.

Snapshots are another feature of ZFS that allows for point-in-time copies of file systems. This is useful for backup and recovery as well as testing and development. ZFS snapshots are extremely efficient, consuming no additional disc space unless data is updated after the snapshot is taken.

ZFS also contains compression, deduplication, and encryption features. Compression uses less disc space by compressing data before it is written on disc. Deduplication reduces duplicate data by storing only a single copy of each unique block, which can save a large amount of space. Encryption secures data by encrypting it before it is written to disc.

What is UFS?

UFS organises data into file systems, which are collections of files and directories stored on a disc or other storage device. Each file system has a size restriction that must be properly set and handled. Basic file permissions and ownership settings are also available in UFS for managing access to files and directories.

One of UFS's benefits is its simplicity and efficiency. It has a relatively low overhead and uses few resources, making it an excellent alternative for smaller systems or systems with limited resources. UFS is also known for its dependability, having mechanisms built in to avoid data corruption and maintain data integrity.

UFS does not have several of the more complex features seen in modern file systems, such as dynamic storage allocation and data redundancy. For data security, UFS instead relies on classic RAID (a redundant array of independent discs) or other data redundancy techniques.

UFS also lacks some advanced file system features, such as snapshots, compression, and encryption. These features, while accessible through third- party utilities or add-ons, are not included in the core UFS file system.

Difference between ZFS and UFS

The following table highlights the major differences between ZFS and UFS −




Stands for

Zettabyte File System (ZFS)

Unix File System (UFS)

Data Integrity

ZFS uses the checksums to verify the data's integrity.

No built-in data integrity checks

Storage Management

It uses a storage pool that can be dynamically resized.

It uses individual file systems that must be explicitly sized and managed.


High Scalability

Low Scalability

Advanced Features

It offers advanced features such as compression, deduplication, and encryption.

It lacks some of the advanced features, such as compression, deduplication, and encryption.


Higher Overhead

Lower Overhead


It is popular for modern Linux-based systems.

It is a popular choice for many Unix-based systems.


It supports efficient point-in- time copies of file systems.

It has no built-in snapshot functionality.


In conclusion, while both ZFS and UFS are file systems used in Unix-based operating systems, ZFS is more scalable, has stronger data integrity features, supports snapshots, and performs better overall than UFS. However, UFS is simpler and has a more permissive license.

Updated on: 02-May-2023


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