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On Tue, Sep 16, 2025 at 09:33:26PM -0400, Garrett Wollman wrote: > <<On Fri, 12 Sep 2025 21:35:26 -0400, Garrett Wollman <wollman@bimajority.org> said: > > > The point being that the ARC is supposed to respond to backpressure > > long before memory runs out. And again, we're talking about a system > > with 100 GiB of outright FREE physical memory. There's no possible > > way that can be fully allocated in less than 5 minutes -- the NICs > > aren't that fast and the servers aren't doing anything else. > > The past couple of nights we've had failures of other NFS servers > (same FreeBSD build, different hardware, different clients, different > data). The most recent one, unlike the one I started this thread > with, didn't get so far as to invoke the OOM killer -- it seems to > have been stuck in arc_wait_for_eviction(). I wasn't in a position to > get a backtrace, so I can't tell if this was the call from > arc_get_data_impl() (which is called for every block allocated but > normally just returns immediately) or the one from arc_lowmem() (which > is ultimately called from the vm_lowmem event handler when the system > is really out of memory). > > As with previous failures, this one was with plenty of physical memory > seemingly available (20 GiB out of 96 GiB). Separate swap partition, > of course, and after 34 minutes memory allocation is pretty much back > to where it was before the crash. Sorry to chime in late. Is this a NUMA system by any chance? That is, what does sysctl vm.ndomains report?
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