In simple terms, the filesystem is a database containing physical locations of files and data for easy retrieval at the time when it is needed. With the help of the Filesystem, the operating system controls how the data is stored and retrieved. File System usually contains files separated into groups known as directories which can hold files and furthermore directories in them. Also helps the system to store the files in the most efficient way possible.
Example:
- Ext4 and Btrfs Filesystems are pretty much well known for their performance in Linux environments.
- NTFS and FAT are known in Windows environments.
1. Ext4 Filesystem:
A filesystem that is well known for its performance and reliability with added metadata and checksums. It is an extent-based filesystem that is used to describe long, physically contiguous files in a single inode pointer entry hence reducing the number of pointers. Fragmentation is also less in this filesystem. It uses delayed allocation to allow the filesystem to collect data that is to be written to the disk before allocating space for it. All these features make it very efficient and reliable than the older versions of Ext filesystems.
2. Btrfs Filesystem:
Btrfs is a copy-on-write (COW) filesystem that focuses mainly on ease in repair and administration. Btrfs eliminates the risk of corruption of data and inaccuracy in data. It is extent based filesystem with huge file size support up to 2 powered 64 (2^64) bytes. It has dynamic inode allocation because of which we can create as many files as we want until we have free space. Also, its name comes from B-trees, which the filesystem uses to store internal file structures for efficient processing of files.
Note:
- After Btrfs filesystem gets fully developed or maybe in a few years when all its features are stable, Ext4 might get replaced by it.
- Creating a file or directory with the name ‘.’ and ‘..’ in both the Ext4 or Btrfs filesystem is not possible.
Feature Comparison between Ext4 and Btrfs:
We will compare the file systems based on the given features:
- Type: It could be Journaling or Copy-on-Write.
- Deduplication: A method with which a file system can remove duplicate copies of some data so as to be storage efficient.
- File-System Compression: The method with which the data automatically gets compressed when it is written in the file system.
- Checksum: Ensures Data Integrity and avoid corruption of user’s data.
- Snapshot: It is a sub-volume that shares all data along with the information related to the specific data(metadata) with another sub-volume.
- Storage Efficiency: With the help of Block Suballocation and tail-packing methods a large file is stored in blocks and in the tail space in the last block it stores some part of another file block. It also helps in increasing the system’s performance.
- Maximum Number of Files: Number of Files we can store in respective filesystems.
- Maximum File Size and Partition size: Maximum Size of File and Partition we can create in the respective filesystems,
Comparison Table
|
Feature |
Ext4 |
Btrfs |
|---|---|---|
| Type of FileSystem | Journaling | Copy on Write(COW) |
| Deduplication | Not supported | Supported |
| File-System Compression | Not Supported | Supported |
| Data Integrity | Not Ensured | Ensured via CRC32C checksum |
| Snapshot | Not supported | Supported |
| Storage Efficiency | Not better than Btrfs | Better than Ext4 |
| Maximum Number of Files | ~4 Billion (2^32) | ~18 quintillions (2^64) |
| Maximum Partition Size and File size |
File Size: 16TiB Partition Size: 1 exbibyte |
File Size: 16EiB Partition Size: 16EiB |
Advantages of Ext4 over Btrfs:
- Ext4 is a reliable and stable filesystem that keeps our data safe in most unwanted events like power loss.
- It has been used for a long time hence testing and bug fixes have improved it a lot.
- Ext4 transfers file faster than Btrfs hence it is a good choice for users.
Advantages of Btrfs over Ext4:
- Btrfs uses a checksum to ensure that the data doesn’t corrupt, on the other hand, Ext4 doesn’t ensure data integrity.
- Btrfs come with compression algorithms present in the filesystem, allowing data to be compressed at the filesystem level right when written to the system.No such built-in compression support is in Ext4.
- Btrfs removes duplicate data from disk directly while Ext4 cannot do that,
- Btrfs support CoW so users can create writable and read-only snapshots of files. Ext4 lacks this feature.
- Btrfs Can handle more data than Ext4.
Conclusion:
Ext4 is stable which ensures the safety of data and also faster. Hence it being in use for so long with bugs-fixes makes it a better choice in the present as it is much more reliable.