Date: Thu, 4 Feb 2016 11:45:56 +1030 From: Shane Ambler <FreeBSD@ShaneWare.Biz> To: Peter Jeremy <peter@rulingia.com> Cc: stable@FreeBSD.org Subject: Re: 10-STABLE hangups frequently Message-ID: <56B2A64C.3050107@ShaneWare.Biz> In-Reply-To: <20160203190323.GC78969@server.rulingia.com> References: <ygeegcvpmv1.wl-ume@mahoroba.org> <20160202183913.GG8270@graf.pompo.net> <56B1B1E9.2090707@ShaneWare.Biz> <20160203190323.GC78969@server.rulingia.com>
next in thread | previous in thread | raw e-mail | index | archive | help
On 04/02/2016 05:33, Peter Jeremy wrote: > On 2016-Feb-03 18:23:13 +1030, Shane Ambler <FreeBSD@ShaneWare.Biz> wrote: >> Any chance you get high wired allocations? > > A high wired allocation is normal for ZFS - ARC shows up as "wired" > memory. > >> Sometimes several times in a day I see the wired amount shown in top >> rise to over 6GB (of 8GB) bringing the system to a crawl. When wired >> gets over 7GB the system rarely recovers. > > The ARC limit defaults to 1GB less than physical RAM so 6GB wired on > an 8GB system isn't unexpected (my home system currently has 30GB > wired out of 32GB). If this is causing problems for your workload, it > sounds like you may need to explicitly reduce vfs.zfs.arc_max (note > that this is a soft limit). I have vfs.zfs.arc_max=2G - and now realise I also had set vfs.zfs.arc_min=500M some time ago. Don't recall where I got it but I also have vfs.zfs.dirty_data_max=200M Going by figures shown in top, ARC is usually in the 1500M to 2000M range but when wired gets over 6GB I often see ARC drop to 500MB which I now realise matches arc_min. When wired gets over 6GB apps start to stop responding, I then try to push out some wired by running a script that allocates 4G, 9 times out of 10 this drops wired to under 4GB and everything keeps working. If I notice wired over 7GB there's usually no recover. I don't always get to see the figures before it totally locks up. On desktop1 I leave a terminal running top and another ready to run my script to allocate some ram. When an app stops responding I go to desktop1 and depending on what I see I manually allocate some ram to flush things out. Currently I have an uptime of 9 days 9 hours - I have manually allocated 4GB 30 times in that time. -- FreeBSD - the place to B...Software Developing Shane Ambler
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?56B2A64C.3050107>