Software RAID

Introduction

Software RAID is an alternative for using hardware-RAID controller for local storage. Please note that Proxmox VE currently only supports one technology for local software defined RAID storage: ZFS

Supported Technologies

ZFS

If you want to run a supported configuration, using a proven enterprise storage technology, with data integrity checks and auto-repair capabilities ZFS is the right choice.

See the ZFS on Linux article for more information.

Technology Preview

btrfs

btrfs can actually be a safe and functional choice, it is supported as technology preview since Proxmox VE 7.

Unsupported Technologies

mdraid

mdraid has zero checks for bit-rot, data integrity, and file systems commonly used on top do not provide that either.

That means, if some data gets corrupted, which happens on any long-running system sooner or later, and you normally do not notice until it's too late. So, Proxmox projects do not support this technology to avoid that users that are not aware of this and its implications run into these problems! Its user experience is also less polished than that of ZFS, and while it might provide slightly more performance in some cases, this is only achieved due too not having the safety-guarantees that, e.g. ZFS provides.

For non-production/unsupported setups, where you still want to use mdraid (please don't!), you can create the required RAID level during Debian installation and then install Proxmox VE or create RAID after install Proxmox VE. See Install Proxmox VE on Debian 12 Bookworm.

If you need further assistance for md-raid, it's another good sign that you do not want to choose that technology.