ZFS File System on NAS: Disadvantages and Worth of the Extra Cost

When it comes to Network Attached Storage (NAS) devices, the choice of file system can significantly impact performance and cost-efficiency. One such file system is ZFS, which has garnered attention for its advanced features and reliability. However, many users are left questioning whether the advantages of ZFS outweigh the potential drawbacks, especially when considering the cost implications. In this article, we explore the disadvantages of using a ZFS file system on a NAS device like Drobo, as well as the potential benefits and cost considerations.

Disadvantages of ZFS on NAS Devices

Legal and Licensing Issues in Linux Environments:

One of the primary concerns with using ZFS on Linux-based NAS devices is the legal and licensing complications. The ZFS file system, originally developed by Sun Microsystems and later acquired by Oracle, has a license that is incompatible with the GNU General Public License (GPLv2). As a result, using ZFS in a Linux environment can lead to significant legal risks. According to the Linux Community, there is currently no official support for ZFS in the Linux kernel. The unofficial support that exists is often considered illegal to use, as it can violate the license terms. This can leave users or those who provide such solutions at risk of legal action if they are discovered to be using it.

No Performance Advantages Over Native Alternatives:

Despite its advanced features, benchmarks have shown that ZFS does not offer a significant performance advantage over native file systems available on Linux. This means that if you are satisfied with your current file system and do not require the additional features provided by ZFS, there is no compelling reason to switch. For most users, sticking with native file systems offers a more cost-effective solution without the added risks.

Balancing Performance and Memory Requirements

Memory Requirements:

A key disadvantage of ZFS, particularly when leveraged with features like deduplication, is its substantial memory overhead. In the best-case scenario, ZFS can consume a significant amount of memory, and when deduplication is enabled, the memory requirements can skyrocket. This can make ZFS a less viable option for systems with limited memory resources. While other file systems like Btrfs can be viable alternatives in such scenarios, ZFS may require 2-4 times the amount of memory just for the filesystem alone, even when the chosen filesystem is large enough to make the choice meaningful.

Performance Degradation on Magnetic Drives:

A notable downside of ZFS is its behavior with database systems and file systems that require contiguous storage. ZFS’s copy-on-write model can cause ongoing and progressive performance degradation, especially on magnetic platter hard drives. While the performance effects are minimized on SSD drives, the write operations can still reduce the effective lifetime of the drive. This is especially true when drives are operating at near capacity levels, leading to a greater number of cells being written during any given period.

Should You Pay Extra for ZFS or Stick with Current File Systems?

Whether you should pay extra for ZFS on your NAS device depends on your specific needs and the features you require. If you need advanced features such as thin provisioning, snapshots, and data integrity checks, then ZFS might be worth the additional cost. However, if you are content with your current file system and do not require these features, it may not be worth the extra expense.

For users who are aware of the ZFS features and its limitations, it is recommended to give it a try. Otherwise, sticking with a proven and more memory-efficient file system, such as Btrfs, can offer a better balance of performance and cost. When considering a solution like Drobo, it is essential to weigh the potential benefits against the potential drawbacks before making a decision.

Conclusion

In conclusion, while ZFS offers many advanced features and benefits, it also comes with significant memory requirements and potential performance issues, particularly on magnetic drives. The choice of whether to invest in a ZFS-based NAS device like Drobo depends on your specific use case and requirements. If you require the advanced features and are willing to accept the trade-offs, then ZFS may be worth the additional cost. However, for most users, other file systems and alternative NAS devices can offer a more efficient and cost-effective solution.