Skip site navigation (1)Skip section navigation (2)
Date:      Fri, 03 Aug 2018 08:57:05 +0000
From:      bugzilla-noreply@freebsd.org
To:        fs@FreeBSD.org
Subject:   [Bug 229986] Terminating virtualbox or ctld + zfs scrub + gstat leads to deadlock
Message-ID:  <bug-229986-3630-Y4i7IlyiR5@https.bugs.freebsd.org/bugzilla/>
In-Reply-To: <bug-229986-3630@https.bugs.freebsd.org/bugzilla/>
References:  <bug-229986-3630@https.bugs.freebsd.org/bugzilla/>

next in thread | previous in thread | raw e-mail | index | archive | help
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 the assignee for the bug.=



Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?bug-229986-3630-Y4i7IlyiR5>