Re: practical experience of FreeBSD > 1TiB RAM

In reply to: Dave Cottlehuber: "practical experience of FreeBSD > 1TiB RAM"
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From: Dirk-Willem van Gulik <dirkx_at_webweaving.org>
Date: Sun, 25 Jan 2026 16:15:20 UTC

On 25 Jan 2026, at 15:57, Dave Cottlehuber <dch@skunkwerks.at> wrote:

> Is anybody using production FreeBSD systems with 1-2 TiB+ RAM?
> This is larger than most FreeBSD systems I've dealt with personally.
> 
> I'm interested in any aspects of tuning & performance you might have
> encountered.
> 
> Workload is PostgreSQL on ZFS, possibly with co-located applications.

Found this to work well out of the box.

But we did increased kern.ipc.maxsockbuf, net.inet.tcp.sendbuf_max/recvbuf_max to 64M (with auto tuning left on) and increased vfs.zfs.arc_max to well over half the memory (basically until zfs-stats gaven sensible ARC numbers (~77% in use; frequently used is 86%; throttle always 0). But we have a lot of indexes and little churn on this database. And lots of readers. And things never get near swapping.

Dw