Date: Tue, 26 Jun 2012 13:30:07 -0400 From: John Baldwin <jhb@freebsd.org> To: freebsd-fs@freebsd.org Cc: Mark Felder <feld@feld.me>, Andriy Gapon <avg@freebsd.org> Subject: Re: [PATCH] Simple ARC stats in top Message-ID: <201206261330.07997.jhb@freebsd.org> In-Reply-To: <4FE9DE92.3040700@FreeBSD.org> References: <201206251443.41768.jhb@freebsd.org> <op.wgio9gg934t2sn@tech304> <4FE9DE92.3040700@FreeBSD.org>
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On Tuesday, June 26, 2012 12:08:50 pm Andriy Gapon wrote: > on 26/06/2012 18:57 Mark Felder said the following: > > On Tue, 26 Jun 2012 10:55:12 -0500, Andriy Gapon <avg@freebsd.org> wrote: > > > >> Does your system also has L2 ARC? > >> If so, could you please show a value of kstat.zfs.misc.arcstats.l2_hdr_size? > >> Otherwise, it's hard for me to explain the huge difference between Max Size and > >> ARC Size. > > > > Yes, it does. > > > > zfs2# sysctl kstat.zfs.misc.arcstats.l2_hdr_size > > kstat.zfs.misc.arcstats.l2_hdr_size: 6775072568 > > Aha, so no mystery, those 6G in ARC are actually used by L2ARC headers. > I missed the L2 headers because I haven't used L2 yet. > I've updated arc-sizes.sh script now to account for these headers. > > So the correct ARC size breakdown is: hdr_size + data_size + other_size + > l2_hdr_size, where data_size can further be broken down to mfu_size + mru_size + > anon_size. Hmm, I think for top I should just use hdr_size + l2_hdr_size for "Headers"? I don't think we have room for more types. I've updated top_arc.patch to take that approach. -- John Baldwin
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