ZFS on Proxmox: How to tune ARC, datasets, and snapshots for production

ZFS is a feature-rich storage system that integrates RAID, copy-on-write, and checksums, making it a strong choice for Proxmox production environments. Administrators can improve performance by creating separate datasets with optimized record sizes — such as 128K for VM images and 16K for databases — and enabling compression. ZFS snapshots enable efficient backups and VM rollbacks, but performance can degrade significantly beyond 1,000 snapshots per dataset, making automated cleanup essential. The Adaptive Replacement Cache (ARC) requires deliberate tuning on hypervisors, including disabling prefetch and setting a measured cap on zfs_arc_max rather than relying on the outdated 50%-of-RAM default. Common pitfalls include using hardware RAID controllers instead of HBA/JBOD mode, adding L2ARC without sufficient primary ARC, and placing the ZFS Intent Log on slow disks.