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Comment by kro | Hacker News Reader

Hetzner normally advertises their hardware servers as 2x 1 TB SSD, because it's strongly recommended to run them in SWraid1 for net 1TB. (Their image installer will default to that)

Once the first SSD fails after some years, and your monitoring catches that, you can either migrate to a new box, find another intermediate solution/replica, or let them hotswap it while the other drive takes on.

Of course though, going to physical servers loses redundency of the cloud, but that's something you need to price in when looking at the savings and deciding your risk model.

And yes, running this without also at least daily snapshotting/backup to remote storage is insane - that applies to cloud aswell, albeit easier to setup there.

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For over a decade I ran a small scale dedicated and virtual hosting business (hundreds of machines) and the sort of setup you describe works very well. Software RAID across 2 devices, redundant power supplies, backups. We never had a significant data loss event that I recall (significant = beyond user accidentally removing files).

For quite a while we ran single power supplies because they were pretty high quality, but then Supermicro went through a ~6 month period where basically every power supply in machines we got during that time failed within a year, and replacements were hard to come by (because of high demand, because of failures), and we switched to redundant. This was all cost savings trade-offs. When running single power supplies, we had in-rack Auto Transfer Switches, so that the single power supplies could survive A or B side power failure.

But, and this is important, we were monitoring the systems for drive failures and replacing them within 24 hours. Ditto for power supplies. If you don't monitor your hardware for failure, redundancy doesn't mean anything.

> But, and this is important, we were monitoring the systems for drive failures and replacing them within 24 hours. Ditto for power supplies. If you don't monitor your hardware for failure, redundancy doesn't mean anything.

It does still mean something.

If you have a 5% annual chance of failure and no redundancy, your five year failure chance is 23%.

If you have redundancy and literally never check for five years, your five year failure chance is 5%. That's already a huge improvement. If you do an inventory of broken parts twice a year, still no proper monitoring, it goes down to 0.6%

For 2% the numbers are: 10% 1% 0.1%

For 10% the numbers are: 41% 17% 2.6%

(The approximations for small percents are x*5, x²*25, and x²*2.5)

Do not rely on raid alone.

Have 2x servers atleast then invest in proper monitoring.

Server can fail without disk failures.

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