work in progress.
A fast and reliable storage controller is one of the most important parts of a Proxmox VE server. This article lists some good working hardware raid controllers and some information about the used configurations. If you wonder how to figure out which Controller you have, log into your Proxmox server and type 'lspci' on the commandline. Then look for a line with RAID Controller or similar.
9690SA SAS/SATA-II RAID PCIe (rev 01)
This Adapter is working well under Proxmox. Attention: make sure you have write cache enabled and use a BBU! Without write cache the vms seem to 'hang' or 'freeze' sometimes. Performance give about 50MB/s on a Raid 5 with 3 HDD's a 1TB
All Adaptec controllers with BBU unit are known to perform well. If possible, take one with "Zero-Maintenance Cache Protection", e.g. Adaptec 5805Z.
Adaptec 2405 Controller completely working (RAID10), out of the box. But be aware, it has no possibility to extend it with an BBU (Battery Backup Unit).
HighPoint 3510 - RAID 10. Works very well.