Cloud storage is really expensive, though. Putting 4 TB in S3 costs US$94.21/month before any transfer costs. A 4 TB CMR HDD is ~$140. That doesn’t include power costs, but over a year you get $990 to spend on that and other things from the cost difference vs. S3 (plus you can sell your old drives when you’re done with them).
(I use B2 for cloud storage backup since it’s a lot cheaper than S3 at US$20 for 4 TB, but that still is ~$105/year more than local)
And that's with bad pricing! Last year, 4TB was $120 and 6TB was ~$150.
Building out a NAS for $1000 ($600 in 4x hard drives, $400 for other components) is very reasonable. Last year that was 4x6TB == 12TB storage + 12TB redundancy, but this year prices are worse so you "only" get 8TB + 8TB redundancy.
$400 can afford a Synology or various NAS devices. It can also afford a new desktop that you can install FreeNAS or whatever onto.
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Eventually, when the 8TB is not enough, just buy a new HBA card and shove 4x more hard drives in there for a 2nd storage on the same NAS. Maybe 8TB x 4 == 16TB usable + 16TB redundancy.
Except no need to copy everything over, just keep the old 8TB cluster working, and just start writing to the new 16TB storage.
> Putting 4 TB in S3 costs US$94.21/month before any transfer costs.
If you have 5TB of photos, chances are you're not looking through 5TB of photos all that often, and S3's IA storage is very appealing at ~$65/mo.
If you only want a cold storage backup, glacier will keep them for you at $20/mo. If you need storage that's only accessed once or twice a year (and you don't mind waiting a bit to get your file) you can pay less than $5/mo with Glacier Deep Archive.
The cost of S3 that you quoted is for _nine nines_ of durability and milliseconds latency. If you don't need that, you can pay for far cheaper storage that better-matches your needs, with the convenience of never needing to buy/transfer/replace/sell drives.
> That doesn’t include power costs, but over a year you get $990 to spend on that and other things from the cost difference vs. S3
If you spend ~days each year worrying about storage and paying for ever-larger disks (and spending time selling your old ones, for whatever you can get), chances are the few hundred dollars you might come out ahead doing it yourself isn't really worth it.
Cloud storage is doing a LOT more than what you describe: for example, to compare with S3 you'd be budgeting for at least 3 disks in geographically separated locations running a secure always-online service with things like guarantees for immutability and bit-rot detection/prevention. For backups, you probably also want to compare things like the infrequent or cold storage tiers.
You can still beat that, of course, but it's assuming you have time and skills to do so and don't mind spending that time playing sysadmin.
Cloud storage is also really different from a hard disk though, mostly in the direction of being really better than a hard disk, so it being more expensive is not surprising.
(I use B2 for cloud storage backup since it’s a lot cheaper than S3 at US$20 for 4 TB, but that still is ~$105/year more than local)