[magicalhippo]

> That was always FUD more or less.

To give some context. ZFS support de-duplication, and until fairly recently, the de-duplication data structures had to be resident in memory.

So if you used de-duplication earlier, then yes, you absolutely did need a certain amount of memory per byte stored.

However, there is absolutely no requirement to use de-duplication, and without it the memory requirements are just a small, fairly fixed amount.

It'll store writes in memory until it commits them in a so-called transaction group, so you need to have room for that. But the limits on a transaction group is configurable, so you can lower the defaults.

[doublepg23]

I don’t think I came across anyone suggesting zfs dedupe without insisting that it was effectively broken except for very specific workloads.