Best Cache Option Proxmox

proxmox-cache.md

Best Cache Option Proxmox

The best cache option in Proxmox depends on your storage type, performance needs, and data safety requirements.

• For local SSDs or fast storage with a BBU-backed RAID controller: Use cache=writeback for best performance, especially for write-heavy workloads. It offers high IOPS but carries a risk of data loss during power failure. Ensure you have a UPS and proper backup.

• For SANs, NFS, or remote storage (e.g., Synology, Ceph): Use cache=none or cache=writethrough. Most SANs already have internal write-back caching, so enabling writeback at the Proxmox level provides little benefit and may increase risk. cache=none bypasses the host page cache, reducing overhead and improving consistency with remote storage.

• For ZFS storage: cache=none is often recommended, as ZFS already manages its own ARC (cache). Enabling additional caching can cause performance degradation due to double buffering.

• For Windows VMs: Some users report better boot times and responsiveness with cache=none when using VirtIO SCSI, despite theoretical benefits of writeback.

Key recommendation: Always prioritize data safety over raw speed. Use cache=none for production environments where data integrity is critical. Use writeback only if you accept the risk and have proper safeguards (UPS, backups, stable power).

For detailed guidance, see: Proxmox Performance Tweaks - Official Wiki.