I'm just confused about a few things, because I don't feel enlightened enough about the whole "proxmox not supporting SW RAID"... people keep bringing up the prob of performance but then argue about RAID 5. That seems akin to comparing the top speed of diferent tractors. Ok, so the hw one is faster... bu it's still slow as hell, specially when degraded.
Also, it's true that power loss isn't the only failure a server may suffer that could cause data corruption, but if HW RAID is better to minimize that, a decent UPS, redundat PSUs with different phases, a good backup policy, etc, etc, can make the extra protection hw raid give meaningless. RAID is not backup. RAID is not redundandy (for services, I mean). RAID is nowhere near perfect. If you read up on ZFS, you can see the ton of design flaws inherent to raid's design and specifications. It's a CHEAP (or it should be) way to make sure that the loss of a disk doesn't bring a server down or destroys data. The key part, for me, it's cheap. With €200, I can buy, for instance, a pair of decent 500GB sata disks. With that, I can use (assume a small server) raid 10 instead of RAID 5. Faster and more reliable for sure. Cheap too. Makes the inexpensive part of RAID somewhat more acurate.
If I can have HW raid, I'll have it. If I can't, because I have no budget available or have something akin to 100 servers and the loss of one is just an inconvinient, I'll choose SW. At least if a HDD fails, the server doesn't. Better than the alternative. In either case, the difference in performance is not relevant.
But please, feel free to ignore this reply. I'm sure hw raid is the only answer that actually makes sense.