New drives are around $16-$20/TB depending on if you catch a sale and are willing to shuck. You can pick up used SAS drives in 3-4TB capacity for around $5/TB. I'm a crazy person, so I built this to hold 11 3TB SAS drives:
I used a Supermicro MB and ECC RAM. It's not much more expensive and it's nice having IPMI. I personally think it's crazy to forego ECC. The SAS controller, expander, and drives were used, everything else was new. Prices have gone up. The new parts were $638 at the time. The drives were ~$20/ea. The HBA and expander were ~$85 for both. After the fans, cables, extra drive cage and brackets, total cost was around $1K. This hardware is all supported out-of-the-box by TrueNAS. I haven't done the math to figure out when the cost of running this will exceed having purchased higher capacity drives.
This is what a typical used SAS drive looks like. 30K hours hours but very few on/off cycles. Zero defect list:
A few drives arrived with a non-zero defect list or otherwise failed burn-in. I contacted the seller on eBay and they sent me replacements w/o any fuss. I'm not necessarily recommending used SAS drives, but I'm not recommended against them either. I will recommend the serverbuilds forum for generally good advice on all this. I think this post got me started:
The catch with shucking drives from cheap NAS systems like from WD is that those drives have a strong likelihood of being SMR drives instead of CMR. Basically, they'll work fine until something goes wrong requiring, say, a RAID rebuild, and then you'll be out weeks while they rebuild begging that they don't fail in the process because the random write performance is abominable.
SMR only affects writes, so assuming you're originally fine with SMR (let's say you only write to the pool very sparingly), you can start off with SMR but then use CMR for replacements.
The pictures inside your case give me anxiety for some weird reason. That's the cleanest* inside of a PC I've seen in my life, almost artificial looking; are you building in a clean room?
I built it in my basement. Why would a newly built PC have any dust?
I'm sad you don't think much of the cable management. I think I did pretty good considering there's 11 drives, 6 fans, and I wasn't able to use custom lengths on any of the cables.
https://imgur.com/a/JqbBN1p
https://pcpartpicker.com/list/dLhNvf
I used a Supermicro MB and ECC RAM. It's not much more expensive and it's nice having IPMI. I personally think it's crazy to forego ECC. The SAS controller, expander, and drives were used, everything else was new. Prices have gone up. The new parts were $638 at the time. The drives were ~$20/ea. The HBA and expander were ~$85 for both. After the fans, cables, extra drive cage and brackets, total cost was around $1K. This hardware is all supported out-of-the-box by TrueNAS. I haven't done the math to figure out when the cost of running this will exceed having purchased higher capacity drives.
This is what a typical used SAS drive looks like. 30K hours hours but very few on/off cycles. Zero defect list:
https://pastebin.com/WcUYX4JR
The failed SMART test turned out to be a firmware issue. I had to update the firmware on all the drives. That was a bit of an adventure:
https://pastebin.com/j3AGX0xN
A few drives arrived with a non-zero defect list or otherwise failed burn-in. I contacted the seller on eBay and they sent me replacements w/o any fuss. I'm not necessarily recommending used SAS drives, but I'm not recommended against them either. I will recommend the serverbuilds forum for generally good advice on all this. I think this post got me started:
https://forums.serverbuilds.net/t/another-nas-killer-4-0-bui...
The current NAS killer version is 5.0:
https://forums.serverbuilds.net/c/builds/18