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by beagle3 4276 days ago
How much memory does ZFS (and/or ZoL) need per 1TB of storage when dedup is off?

Also, bup ("it backs things up!") efficiently dedups across an ssh connection (using bloom filters) Scales are differrent, but it might work for ZFS as well.

2 comments

I answered this question here:

https://news.ycombinator.com/item?id=8437921

The recommendations I've read say you need 1GB RAM for system use (assuming a dedicated file server), and then as much RAM (ideally ECC RAM) as you want to give it for caching data.

If you're short on RAM (sub 4GB), you might need to change some of the default settings to avoid problems, but RAM's fairly cheap nowadays, so unless you've got an old machine, it's not likely to be a problem :)

I'd point out that cheap ram is about $10/GB right now, and a cheap HDD is $30/TB. So if you need an extra GB of ram for each TB of storage, you're increasing storage costs by a third.