## SMR Vs CMR Drives When choosing between **SMR (Shingled Magnetic Recording)** and **CMR (Conventional Magnetic Recording)** drives for ZFS, there are significant differences that affect performance and reliability in ZFS environments. Use **CMR** drives for ZFS: They handle ZFS's random write patterns, scrubbing, and resilvering efficiently, ensuring better performance and reliability. Avoid **SMR** drives for ZFS pools: Their slow random write performance and poor handling of write-intensive tasks make them unsuitable for primary storage, though they can work for backups or cold storage. ZFS's write amplification makes CMR the better choice for long-term integrity and usability. While SMR drives like the WD Red 4TB SMR can offer higher data density, their performance, particularly in RAID array rebuilds, is significantly inferior to CMR drives. This can be a critical factor for NAS users, suggesting that CMR drives are a better choice for such applications ([source](https://www.servethehome.com/wd-red-smr-vs-cmr-tested-avoid-red-smr/)).