Date: Mon, 19 Sep 2011 14:37:46 -0700 From: Artem Belevich <art@freebsd.org> To: Freddie Cash <fjwcash@gmail.com> Cc: Jason Usher <jusher71@yahoo.com>, freebsd-fs@freebsd.org Subject: Re: ZFS obn FreeBSD hardware model for 48 or 96 sata3 paths... Message-ID: <CAFqOu6herryuJaZmN2xc_xafUPMQOpU3mt-rO_GCvsjdigEjoQ@mail.gmail.com> In-Reply-To: <CAOjFWZ6Y4PbAaZzMxyzZHmtrNBJzOK8GMVJL0GP0PMdwj9SeXg@mail.gmail.com> References: <alpine.GSO.2.01.1109171451500.1973@freddy.simplesystems.org> <1316459220.35419.YahooMailClassic@web121209.mail.ne1.yahoo.com> <CAOjFWZ6Y4PbAaZzMxyzZHmtrNBJzOK8GMVJL0GP0PMdwj9SeXg@mail.gmail.com>
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On Mon, Sep 19, 2011 at 1:27 PM, Freddie Cash <fjwcash@gmail.com> wrote: >> Can I explicitly cache metadata/dirs in RAM, and cache file data in L2AR= C ? > > > No. =A0Data that does not go into the ARC can never go into the L2ARC. = =A0IOW, > if you set primarycache=3Dmetadata and secondarycache=3Ddata, you will ne= ver see > anything in L2ARC. > > At least, that's the understanding I've come to based on posts on the > zfs-discuss mailing list. =A0And it does jive with what I was seeing on o= ur > storage servers. Indeed. I didn't think of that. L2ARC is populated by the data that gets evicted from ARC. So, if ARC is metadata only, whatever spills into L2ARC would be metadata only, too... > It's too bad, because it would be a nice setup, ordered from fastert to > slowest: =A0ARC for metadata, L2ARC for file data, pool for permanent sto= rage. That would indeed be nice. --Artem
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