I wouldn't say that being new is an absolute requirement. I recently upgraded my ZFS pool from SATA to SAS HDDs. Since SAS HDDs have much better firmware for early error detection and monitoring, I decided to buy 50% refurbished. Even if I lost half of them, I would still be safe. I also have offsite backups. This setup worked really well for me, and I feel completely confident that my data is safe while not wasting unnecessary resources. Whether to use new or used equipment therefore depends on the setup.
Agree, but that's taking a risk with your data (whereas if a MB fails, you likely just need to replace it but your data is fine), and HDD kind of have a finite number of hours in them. Where buying them used I think makes sense is for a backup server, that you leave off except the few hours in a week where you do an incremental backup. Then it doesn't really matter that the drives have already been running for 3 or 4 years.
With the redundancy in a raidz2 or mirror, the driver can and will fail. I count on this. But it can happen in a controlled manner.
So you buy used enterprise disks because their error detection is 'better'?
Do you have any source for this claim? Why would be the firmware so different? Software is cheap i don't think they would be that different.
I mean a used enterprise disk gets sold after it was running on heavy load for a long time. Any consumer hdd will have a lot less runtime than enterprise disks.
The protocol is better (SAS). Once I put them in, I immediately noticed transmission issues in a counter going up for several of my HDDs where the SATA showed no errors at all. It was a faulty backplane that introduced these transmission issues that went unnoticed by my SATA drives for several years.