Date: Sat, 23 Jan 2010 10:44:28 +0100 From: Alexander Leidinger <Alexander@Leidinger.net> To: jhell <jhell@DataIX.net> Cc: freebsd-hackers@freebsd.org Subject: Re: Setting "zfs_arc_max" value in FreeBSD 8. Message-ID: <20100123104428.000021b5@unknown> In-Reply-To: <alpine.BSF.2.00.1001221933510.92084@pragry.qngnvk.ybpny> References: <7f14551c1001190119x46c6b04dx2362cd1252f0d81@mail.gmail.com> <hj3v0i$i2p$1@ger.gmane.org> <7f14551c1001190216w49814186n1ada2b721380502b@mail.gmail.com> <4B55C5A6.2020109@DataIX.net> <20100120111433.25801pnmhrxnirok@webmail.leidinger.net> <alpine.BSF.2.00.1001221933510.92084@pragry.qngnvk.ybpny>
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On Fri, 22 Jan 2010 20:28:09 -0500 jhell <jhell@DataIX.net> wrote: > > On Wed, 20 Jan 2010 05:14, Alexander@ wrote: > > Quoting jhell <jhell@DataIX.net> (from Tue, 19 Jan 2010 09:45:58 > > -0500): > > > >> On 1/19/2010 5:16 AM, Sherin George wrote: > >>> Thanks Ivan :) > >>> > >>> I found It. add following in /boot/loader.conf > >>> > >>> =================== > >>> vfs.zfs.arc_max="10244M" > >>> =================== > > > >> I just thought I would give a shout at this for stable/7 as of last > >> week. I am not sure if this is just me but I had tried to adjust > >> zfs_arc_max and found out that it was unadjusted to my value after > >> the system came back up. > >> > >> Anyone know if it is adjustable on a system with 1024MB of ram ? > >> Is this just being auto calculated by some other value ? > > > > Can you confirm that you made the modification > > in /boot/loader.conf, and that you used the double-quotes around > > the value as shown above? > > > > The code in 7-stable regarding this is the same as in 8-stable and > > 9-current, so if it is done correctly, it has to change accordingly. > Yes, > > The sysctl in question on my machine is/was put in loader.conf with > the double quotes. > > Every time I have set this before I was trying to set it to a value > >= 512M which with the values below must have not been excepted and > >fell back > to 320M. > > If I set this to a value of <= 511M it works fine which leads me to > believe this is limited by some other value listed below ? It can not be bigger than kmem_max. While I do not know if this is checked, it sounds from your description that it is. > dmesg: > real memory = 1072107520 (1022 MB) > avail memory = 1035038720 (987 MB) > > loader.conf: > kern.maxusers="512" << Not sure if this has anything to do It should influence the kmem_max... if you would not change it yourself. > with it. vfs.zfs.arc_min="80M" > vfs.zfs.arc_max="512M" << This fails. stays at 335544320. It needs to be a lot less than kmem_max (the arc is allocated from the kmem, as such it can not exceed kmem_max, and as other parts of the kernel also need kmem, you need to limit the arc size). On a 32bit system with 1 GB RAM I have kmem_size_max set to 512M and arc_max set to 160M. > vm.kmem_size="512M" > vm.kmem_size_max="512M" << Maybe this one. > kern.ipc.semmni="40" > kern.ipc.semmns="300" > kern.maxdsiz="536870912" > kern.maxfiles="16384" Bye, Alexander.
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