So I’m (finally) trying to tame my digital disaster area (admittedly spurred on by a recently fussy HDD).
All data is backed up (often) so that’s not an issue. This is for desktop use (not in a NAS or Server build).
While my daily driver is Linux Mint I do play with other distros on the same box both in VMs and on bare metal installs.
My current plan is to buy a new hdd (or 2), set it up in mdadm for mirroring and be done with it.
Given my current use case, desktop drives or enterprise is the question.
So using WD as the example this would be WD blacks vs WD Redpro/Gold (me likes 5 year warranty).
There would likely be a max of 3 or 4 HDDs in the system (full size tower), with only the 2 drives in raid.
Obviously in a larger raid (5+) I’d have parity checks for error correction and so the reds & golds count on that, while the blacks use a different approach.
It’s been a long time since I “raided” for this use and find my brain shorting out. Thanks for the help.
SomeDudeInAZ
PS: As a longtime lurker this issue actually spurred me into joining and making my first post. You folks were my thought about whom to ask.
Get which ever is cheapest that will fulfill your storage requirements.
The thing that separates out enterprise drives is a higher write endurance, MTBF, and certain features like firmware and hardware tweaks to work in a high density environment (IE 12+ disks close together).
Since you’re use case is for a local mirror backup (RAID1), you’d probably be perfectly served by any drive honestly.
The thing to look out for these days are SMR drives because they have a write penalty due to their design. They’re honestly fine, I have one. But only as storage that is infrequently written to but mostly just read from. I use it to hold games since after the download it’s just mostly reads.
Unless you can find a really good deal on the enterprise drives. For example I usually buy 8TB helium SAS drives for around $110.
So my advice is to shop around as you’ve got plenty of options.
I’m not sure how MDADM works (I’m a ZFS guy) but if it has timers to determine when a drive has dropped out of the array (e.g., the software waits for X seconds for an op to complete before determining the drive broke), even in a mirror SMR may bite you in the ass - eventually. Because sometimes the SMR drives can take FAR longer to do re-writes than non-SMR drives.
The first write to a section of the disk isn’t the problem, it’s when that area needs to be re-written, it needs to do read-modify-write of the adjacent data that the hosting OS doesn’t necessarily know about.
It will likely be fine until you start re-writing data (e.g., due to a re-build/re-sync or when data on disk needs to change in place). The re-shingling process (which may only start to occur after you have gone some way to filling the drive or need to modify data in place) can result in the drive taking longer to write than the raid software/controller will expect and it may drop it from the array.
At which point you’re up for a re-sync, which may result in exactly the same scenario - ergo (hypothetically speaking here), everything will be fine with your RAID1 until an error actually occurs to incur a rebuild, and then it goes to shit. Kinda defeating the purpose of the mirror.
Definitely look into whether your RAID software will have issues with that, because that sort of thing doesn’t depend on raid level.
I’d steer clear of SMR drives for any sort of RAID personally; the whole point of RAID is resiliency and these drives have shown plenty of times that they just don’t play nice with it.
If you’re stuck with SMR, maybe consider some sort of differential copy over-night instead? You’ll avoid the “array failure on rebuild” issue that seems to be occurring (as you aren’t running an array). You’ll also protect yourself from fat finger deletions, etc. to an extent
You didn’t specify the size(s). If it will fit your needs I’d just as soon as go straight to SSD and forget the HHD. Simpler, more robust and far faster. KISS rules! A 2TB SSD is pretty good and you don’t have to worry about RAID software stability or SMR or any of that crap if you buy the “wrong” HDD.
