Why does QNAP NAS not use the Btrfs file system?
Challenges of using Btrfs for NAS applications
Btrfs is slow
- Btrfs has greater I/O latency. In the same testing environment, file transfer via Samba with the ext4-using QNAP NAS is 61.5% faster than another brand’s NAS that uses Btrfs. In the benchmark report from Phoronix, a leading technology website for Linux hardware reviews, it reveals a similar test result.
Risky for snapshot management
- Although Btrfs supports snapshots, it cannot separate volumes for storing data and snapshot usage. Snapshot files will occupy system storage space, and that increases the difficulty of storage management and puts IT operations at risk.
Storage performance continues to increase
- Traditional hard disks provide 100~150 MB/s and approximately 500 IOPS performance during data access, and can bottleneck overall system performance. While the sequential access speed of current hard disks can rise to 180~220 MB/s, Btrfs with higher I/O latency makes it difficult to realize the full performance potential of hard disks, and is even more inefficient for increasingly-affordable SSDs.
10GbE connectivity benefits
- The total cost of implementing 10GbE network environments continues to fall, allowing more organizations to take advantage of the massive potential performance benefits. However, if the performance bottleneck caused by Btrfs-based NAS is not addressed, it would offset any productivity improvements from 10GbE connectivity and diminish the ROI.
Block-based snapshot is key to defending against Ransomware
- Ransomware has gained greater mainstream awareness in recent times due to high-profile attacks, and it can potentially affect everyone - from home users to multinational companies. To mitigate the threat of ransomware, using block-based LUN snapshots is a recommended practice. Based on the ext4 file-system, QNAP NAS supports not only file-based iSCSI LUN but also block-based iSCSI LUN that are operated separately from the file system to fulfill better data protection. Btrfs-based NAS does not support snapshots for block-based iSCSI LUN.
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