Date: Fri, 03 Aug 2018 08:57:05 +0000 From: bugzilla-noreply@freebsd.org To: virtualization@FreeBSD.org Subject: [Bug 229986] Terminating virtualbox or ctld + zfs scrub + gstat leads to deadlock Message-ID: <bug-229986-27103-ymGVEfbP7Q@https.bugs.freebsd.org/bugzilla/> In-Reply-To: <bug-229986-27103@https.bugs.freebsd.org/bugzilla/> References: <bug-229986-27103@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D229986 --- Comment #9 from Martin Birgmeier <d8zNeCFG@aon.at> --- Actually I am quite sure that the system *is* in a kind of memory deadlock = at least in the case where it ultimately gets stuck completely (comment #4). In that case, if I remember correctly, it also used quite some swap (around 5%= of 20G configured). But for the issue with scrubbing interacting badly with shutting down VMs a= nd stopping ctld, this happens without too much memory pressure. Specifically, I have: - 16G main memory; this initially gives vfs.zfs.arc_max: 15371956224, which= is high, considering that dmesg.boot shows real memory =3D 17179869184 (16384 MB) avail memory =3D 16344322048 (15587 MB) - Then use sysctl vfs.zfs.arc_max=3D9000000000 - The VM run directly on this machine has 3G simulated physical memory The scrub has completed in the meantime, and I don't really want to restart= it, having taken 360 hours in total, and with it being very taxing on the disks= . So it is difficult to replay the scenario now. However, what is still happening and may be related to memory pressure agai= n: When I shut down ctld after many hours of operation of this machine using 'service ctld onestop' (see comment #2), in contrast to 11.1 this operation= may take several minutes. I believe this happens especially if I forget to redu= ce arc_max. In this case again it looks to me like memory pressure and that the system takes a long time to get some free memory which seems to be required for th= is operation. Maybe it is related to zvols, both the VM running directly on the machine as well as the ctld reference zvols. -- Martin --=20 You are receiving this mail because: You are on the CC list for the bug.=
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