I am building a NAS in RAID 1 (Mirror) mode. Should I buy 2 of the same drive from the same manufacturer? or does it not matter so much?
I am building a NAS in RAID 1 (Mirror) mode. Should I buy 2 of the same drive from the same manufacturer? or does it not matter so much?
Quite the opposite. Use drives from as many different manufacturers as you can, especially when buying them at the same time. You want to avoid similar lifecycles and similar potential fabrication defects as much as possible, because those things increase the likelihood that they will fall close to each other - particularly with the stress of rebuilding the first one that failed.
To the best of my knowledge, this “drives from the same batch fail at around the same time” folk wisdom has never been demonstrated in statistical studies. But, I mean, mixing drive models is certainly not going to do any harm.
It may, performance-wise, but usually not enough to matter for a small self-hosting servers.
I wouldn’t mix 5400 rpm drives with 7200 rpm drives, but if the rpm & sizes are the same, there won’t be any measurable performance loss.
If everything went fine during production you’re probably right. But there have definitely been batches of hard disks with production flaws which caused all drives from that batch to fail in a similar way.
I know it’s only what I’ve experienced but I’ve been on a 2 weeks of hell from emc drives failing at the same time because dell didn’t change up serials. Had 20 raid drives all start failing within a few days of each other and all were consecutive serials.
If I had a dollar for every time rebuilding a RAID array after one failed drive caused a second drive failure in the array in less than 24 hours… I’d probably buy groceries for a week.
When using drives from the same model and batch?
Yup. Same age, same design, same failures… and array rebuilds are super intense workloads that often force a lot of random reads and run the drive at 100% load for many hours.