Hello c/homelab!
My NAS currently consists of 6TB of spinning rust, one disk only. As time goes on I increasingly think about how annoying it would be to lose it to a random drive failure.
So, I recently had an idea for a new storage setup when I saw a 2TB M.2 drive for £60-70 online. Given the low price, these drives are likely low-quality and probably cacheless too, but I have a potential solution: If I bought 4 of these and set them up in RAID10, would that be a sensible way to effectively double the speed and increase redundancy?
Yes, I know it's probably a silly idea when I can just spend more on 2 faster and more reliable drives, but I would like to at least hear from people who might have tried something similar! So what do you think?
You probably don’t need that kind of read/write performance in your average NAS because you’re almost certainly going to be network limited. Not sure what the specs on these cheap ones are, but something like a Samsung 970 evo from a few years ago would more than saturate a 10g link, so doubling that wouldn’t really help.
That said, I recently built a 4 M.2 drive raid0 on my homelab server for some read heavy workloads, and things scaled close to how you’d expect with just mdadm+ext4 (about 80% of the drives’ theoretical maximum bandwidth in fio test). If you can actually use the extra IOPS or disk bandwidth, it works pretty well and was easy to do.
I think you're half-right with the speed thing. Cacheless SSDs tend to perform VERY poorly in random 4K reads/writes (like, HDD or even SD-card poorly), so I figured any slowdowns from operations like that could be mitigated. Though I do see the value in just getting 2 better SSDs, I would have to spend even more on higher-capacity drives to make up for the lesser drive count.
Well, I certainly made some assumptions about your workload that may not be true. What do you use it for?
As bulk storage (backups, media streaming, etc), random 4k reads are usually not going to be the limiting factor, except maybe for the occasional indexing by Plex etc. If you’ve instead got lots of small files you’re accessing, or are hosting something like a busy database/web server on here, then you could see significant boost, but not anywhere near as significant as just co-locating the service and the data. If your workload involves a lot of writes, then I would stay away. The MTTF on “cacheless” SSDs is pretty garbage, which seems like the biggest issue to me.
Also, didn’t mean to suggest buying nicer drives, just using an older one I was familiar with as reference. I recently bought the 2TB 970 evo plus on sale for $80 each, which was in your price range, but not sure if that pricing made it to the UK.
My workload is a little mixed. It's mostly media storage, which of course is sequential. But I also occasionally use it to host game servers for my friends and I to play on. Depending on the way each game is written, it's possible it may be reading from random locations to access assets or whatever. I'd rather that, after spending hundreds on an upgrade, the performance at least doesn't get worse.
I'll do some digging into the cost of fewer but more reputable SSDs later. Thanks for your input so far!