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Comment by mcsoft | Hacker News Reader

We have seriously looked at FoundationDB to replace our SQL-based storage for distributed writes. We decided not to proceed unless we are about to overgrow the existing deploy, a standard leader-follower setup on the off-the-shelf hardware. The limiting factor for the latter would be a number of NMVMe drives we could put into a single machine. It gives us couple dozen Tb of structured data (we don't store blobs in the database) before we have to worry.

fdb is best when your workload is pretty well-defined and will stay such for a decade or so. It is not usually the case for new products which evolve fast. Two most famous installations of fdb are iTunes and Snowflake metadata. When you rewrite petabyte-size database in fdb, you transform continuous SRE/devops opex costs into developers capex investment. It comes with reduced risks for occasional data loss. For me it's mostly a financial decision, not really a technical one.

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> transform continuous SRE/devops opex costs into developers capex investment

Would you mind expanding/educating me on this point? When I think of capex I think of “purchasing a thing that’s depreciated over a time window”. If you’d said “transform SRE/COGS costs into developer/R&D/opex costs” I would’ve understood, but eventually the thing leaves development and goes back into COGS.

Basically the SREs don't have anything to do with fdb for the most part. You add a node, quiesce a node, delete a node. Otherwise it's self-balancing and trouble-free from an SRE pov.

See my other message for the developer issues, though. IMHO fdb as it is today is too hard for most developers if their use case is anything beyond redis simple keys.

AIUI:

- developer time is approximately fungible with money - project delivery is building a thing, that you own, and that has value, and that you will use to produce other value... - ...which can therefore be entered on the balance sheet.

I've just left a company a little after it floated. In the run-up to the float, we were directed to maximise our capital time logged. That meant any kind of feature delivery. Bugfixes were opex.

I believe this was done to grow the balance sheet and maximise market cap.

I assume a couple of things here: 1) that SRE costs would be lower with fdb at scale due to its handling outages, i.e. auto-resharding; and 2) that a migration project from *sql to fdb will be finite (hence an investment I hastily called capex).

Would love to hear from anyone with experience in fdb whether these assumptions hold.

Were you planning on using the Record or Document layer if you went with it? Or maybe making your own layer?

We'd use the Record layer, but it was Java-only then. It would require us either to rewrite parts of our backend to Java or to implement some wrappers.

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