@subnetspider@mastodon.bsd.cafe The first port of ZFS to FreeBSD was memory hungry because the buffer cache and ARC both held copies of pages. Every page being accessed used two pages, one in ARC and one in the buffer cache. Around FreeBSD 9ish, the buffer cache was extended to be able to handle pages that it didn’t own, which removed that overhead. ZFS does need a bit more cache than UFS for good performance. The bit that’s still true is that dedup needs a lot of RAM. ZFS needs to probe the dedup tables on each store when dedup is enabled, which means performance rapidly drops off if you start missing on probes.