Comment by csdvrx
7 months ago
For long term storage, prefer hard drives (careful about CMR vs SMR)
If you have specific random IO high performance needs, you can either
- get a SLC drive like https://github.com/openzfs/zfs/discussions/14793
7 months ago
For long term storage, prefer hard drives (careful about CMR vs SMR)
If you have specific random IO high performance needs, you can either
- get a SLC drive like https://github.com/openzfs/zfs/discussions/14793
> - make one yourself by hacking the firmware: https://news.ycombinator.com/item?id=40405578 Be careful when you use something "exotic", and do not trust drives that are too recent to be fully tested
Do you realize the irony of cautioning about buying off the shelf hardware but recommending hacking firmware yourself?
That "firmware hack" is just enabling an option that manufacturers have always had (effectively 100% "SLC cache") but almost always never use for reasons likely to do with planned obsolescence.
Converting a QLC chip into an SLC is not planned obsolescence. It’s a legitimate tradeoff after analyzing the marketplace that existing MTBF write lifetimes are within acceptable consumer limits and consumers would rather have more storage.
Edit: and to preempt the “but make it an option”. That requires support software they may not want to build and support requests from users complaining that toggling SLC mode lost all the data or toggling QLC mode back on did similarly. It’s a valid business decision to not support that kind of product feature.
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They did not recommend. They listed.
Tape is extremely cheap now. I booted up a couple laptops that have been sitting unpowered for over 7 years and the sata SSD in one of them has missing sectors. It had zero issues when shutdown.
Is tape actually cheap? Tape drives seem quite expensive to me, unless I don't have the right references.
Tapes are cheap, tape drives are expensive. Using tape for backups only starts making economic sense when you have enough data to fill dozens or hundreds of tapes. For smaller data sets, hard drives are cheaper.
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If you don’t have a massive amount of data to backup, used LTO5/6 drives are quite cheap, software and drivers is another issue however with a lot of enterprise kit.
The problem ofc is that with a tape you need to also have a backup tape drive on hand.
Overall if you get a good deal you can have a reliable backup setup for less than $1000 with 2 drives and a bunch of tape.
But this is only good if you have single digit of TBs or low double digit of TBs to backup since it’s slow and with a single tape drive you’ll have to swap tapes manually.
LTO5 is 1.5TB and LTO6 is 2.5TB (more with compression) it should be enough for most people.
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The issue with tape is that you have to store it in a temperature controlled environment.
Tape sucks unless you've got massive amounts of money to burn. Not only are tape drives expensive, they only read the last two tape generations. It's entirely possible to end up in a future where your tapes are unreadable.
There's a lot of LTO drives around. I strongly doubt there will be any point in the reasonable lifetime of LTO tapes (let's say 30 years) where you wouldn't be able to get a correct-generation drive pretty easily.
While the tape is relatively cheap, the tape drives are not. The new ones typically starts at 4K USD, although sometimes for older models the prices can drop below 2K.
You can get LTO5+ drives on ebay for $100-400. Buying new doesn't make sense for homelab.
If you care about long term storage, make a NAS and run ZFS scrub (or equivalent) every 6 months. That will check for errors and fix them as they come up.
All error correction has a limit. If too many errors build up, it becomes unrecoverable errors. But as long as you reread and fix them within the error correction region, it's fine.
> run ZFS scrub (or equivalent) every 6 months
zfs in mirror mode offers redundancy at the block level but scrub requires plugging the device
> All error correction has a limit. If too many errors build up, it becomes unrecoverable errors
There are software solutions. You can specify the redundancy you want.
For long term storage, if using a single media that you can't plug and scrub, I recommend par2 (https://en.wikipedia.org/wiki/Parchive?useskin=vector) over NTFS: there are many NTFS file recovery tools, and it shouldn't be too hard to roll your own solution to use the redundancy when a given sector can't be read
What hardware, though? I want to build a NAS / attached storage array but after accidentally purchasing an SMR drive[0] I’m a little hesitant to even confront the project.
A few tens of TBs. Local, not cloud.
[0] Maybe 7 years ago. I don’t know if anything has changed since, e.g. honest, up-front labeling.
[0*] For those unfamiliar, SMR is Shingled Magnetic Recording. https://en.m.wikipedia.org/wiki/Shingled_magnetic_recording
I have a homelab with a bunch of old HP Gen 8 Microservers. They hold 4x 3.5" hdds and also an ssd (internally, replacing the optical slot):
https://www.ebay.com/itm/156749631079
These are reasonably low power, and can take up to 16GB of ECC ram which is fine for small local NAS applications. The cpu is socketed, so I've upgraded most of mine to 4 core / 8 thread Xeons. From rough memory of the last time I measured the power usage at idle, it was around 12w with the drives auto-spun down.
They also have a PCIe slot in the back, though it's older gen, but you'll be able to put a 10GbE card in it if that's your thing.
Software wise, TrueNAS works pretty well. Proxmox works "ok" too, but this isn't a good platform for virtualisation due to the maximum of 16GB ram.
> What hardware, though?
Good question. There seems to be no way to tell whether or not we're gonna get junk when we buy hard drives. Manufacturers got caught putting SMR into NAS drives. Even if you deeply research things before buying, everything could change tomorrow.
Why is this so hard? Why can't we have a CMR drive that just works? That we can expect to last for 10 years? That properly reports I/O errors to the OS?
Toshi Nx00/MG/MN are good picks. The company never failed us and I don't believe they've had the same kinds of controversies as the US competition.
Please don't tell everyone so we can still keep buying them? ;)
The Backblaze Drive Stats are always a good place to start: https://www.backblaze.com/blog/backblaze-drive-stats-for-202...
There might be SMR drives in there, but I suspect not.
Nothing can really save you from accidentally buying the wrong model other than research. For tens of TBs you can use either 4-8 >20TB HDDs or 6-12 8TB SSDs (e.g. Asustor). The difference really comes down to how much you're willing to pay.
SMR will store your data, just slowly.
It was a mistake for the Hard Drive business community to push them so hard IMO. But these days the 20TB+ drives are all HAMR or other heat/energy assisted tech.
If you are buying 8TB or so, just make sure to avoid SMR but otherwise you're fine. Even then, SMR stores data fine, it's just really really slow.
I use TrueNAS and it does a weekly scrub IIRC.
> (careful about CMR vs SMR)
Given the context of long term storage... why?
After I was bamboozled with a SMR drive, always great to just make the callout to those who might be unaware. What a piece of garbage to let vendors upsell higher numbers.
(Yes, I know some applications can be agnostic to SMR, but it should never be used in a general purpose drive).
Untested hypothesis, but I would expect the wider spacing between tracks in CMR makes it more resilient against random bit flips. I'm not aware of any experiments to prove this and it may be worth doing. If the HD manufacture can convince us that SMR is just as reliable for archival storage it would help them sell those drives since right now lots of people are avoiding SMR due to poor performance and the infamy of the bait-and-switch that happened a few years back.