Date: Mon, 3 Oct 2011 07:58:04 -0700 From: Artem Belevich <art@freebsd.org> To: Attila Nagy <bra@fsn.hu> Cc: freebsd-fs@freebsd.org, Adrian Chadd <adrian@freebsd.org>, delphij@freebsd.org Subject: Re: is TMPFS still highly experimental? Message-ID: <CAFqOu6jEoH8oGpy6i_7emUfrNvSG1jtypYza6jgCWVvXB%2Bh4RQ@mail.gmail.com> In-Reply-To: <4E899C8E.7040305@fsn.hu> References: <CAOfDtXMm9K_fbOmvG2gvXxDfKakkgpPt9MLifqDxa4wCibMExg@mail.gmail.com> <alpine.GSO.1.10.1110011122030.882@multics.mit.edu> <CADLo83-s_3H8PbbxOPPxbe0m10U0U5JW-feB294dFs%2BQ3iTWvg@mail.gmail.com> <CAGMYy3ssi%2BkAuufDTHA1z6u7jRrZwRRkCCkcO94GHNGF9Rku_w@mail.gmail.com> <20111002020231.GA70864@icarus.home.lan> <4E899C8E.7040305@fsn.hu>
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> For me, the bug is still here: > $ uname -a > FreeBSD b 8.2-STABLE FreeBSD 8.2-STABLE #5: Wed Sep 14 15:01:25 CEST 2011 > =A0 root@buildervm:/data/usr/obj/data/usr/src/sys/BOOTCLNT =A0amd64 > $ df -h /tmp > Filesystem =A0 =A0Size =A0 =A0Used =A0 Avail Capacity =A0Mounted on > tmpfs =A0 =A0 =A0 =A0 =A0 0B =A0 =A0 =A00B =A0 =A0 =A00B =A0 100% =A0 =A0= /tmp > > I have no swap configured. The machine has 64 GB RAM. > vm.kmem_size=3D60G; vfs.zfs.arc_max=3D55G; vfs.zfs.arc_min=3D20G I'm curious -- does your ARC size ever reaches configured limit of 55G? My hunch that it's probably hovering around some noticeably lower number. On my ZFS setups a lot of memory seems to be lost due to fragmentation. On a system with 24G of RAM and rac_max=3D16G, I typically see more than 20G of memory wired. With kmem_size=3D60G, ARC is likely to use up most of available kmem space and that's probably what affects tmpfs. Besides, with kmem_size that close to arc_max you may be risking meeting "kmem too small" panic, though, considering that your kmem_size is rather large chances of that are smaller than on a system with smaller amounts of memory and kmem_size. I'd start with doubling kmem_size and, possibly, reducing arc_max to the point where it stops putting pressure on tmpfs. --Artem
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