Date: Fri, 29 Apr 2011 12:09:59 +0930 From: "Daniel O'Connor" <doconnor@gsoft.com.au> To: Artem Belevich <art@freebsd.org> Cc: freebsd-stable List <freebsd-stable@freebsd.org>, Jeremy Chadwick <freebsd@jdc.parodius.com> Subject: Re: ZFS vs OSX Time Machine Message-ID: <C70FE41B-3054-49A6-AF96-A7077BBAD078@gsoft.com.au> In-Reply-To: <BANLkTinntrhiKOwaryZNBuf_qt=6kS5oQA@mail.gmail.com> References: <537A8F4F-A302-40F9-92DF-403388D99B4B@gsoft.com.au> <20110428195601.GA31807@icarus.home.lan> <AF725CFF-86A4-4D65-A26E-496F6B9BD33E@gsoft.com.au> <20110429010829.GA36744@icarus.home.lan> <BANLkTinntrhiKOwaryZNBuf_qt=6kS5oQA@mail.gmail.com>
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On 29/04/2011, at 11:43, Artem Belevich wrote: > On Thu, Apr 28, 2011 at 6:08 PM, Jeremy Chadwick > <freebsd@jdc.parodius.com> wrote: >> I will note something, however: your ARC max is set to 3072MB, yet = Wired >> is around 4143MB. Do you have something running on this box that = takes >> up a lot of RAM? mysqld, etc..? I'm trying to account for the = "extra >> gigabyte" in Wired. "top -o res" might help here, but we'd need to = see >> the process list. >>=20 >> I'm thinking something else on your machine is also taking up Wired, >> because your arcstats shows: >>=20 >>> kstat.zfs.misc.arcstats.c: 3221225472 >>> kstat.zfs.misc.arcstats.c_min: 402653184 >>> kstat.zfs.misc.arcstats.c_max: 3221225472 >>> kstat.zfs.misc.arcstats.size: 3221162968 >>=20 >> Which is about 3072MB (there is always some degree of variance). >=20 > The difference is probably due to fragmentation (most of ARC > allocations are served from power-of-2 zones, if I'm not mistaken) + a > lot of wired memory sits in slab allocator caches (FREE column in > vmstat -z). On a system with ARC size of ~16G I regularly see ~22GB > wired. Ona smaller box I get about 7GB wired at around 5.5GB ARC size. This system also does double duty as a desktop PC so it gets a fair = hammering.. It did have 4GB of RAM but that was fairly terrible, 8GB is a lot better = though :) -- Daniel O'Connor software and network engineer for Genesis Software - http://www.gsoft.com.au "The nice thing about standards is that there are so many of them to choose from." -- Andrew Tanenbaum GPG Fingerprint - 5596 B766 97C0 0E94 4347 295E E593 DC20 7B3F CE8C
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