Date: Thu, 10 Oct 2013 10:16:47 -0700 From: Freddie Cash <fjwcash@gmail.com> To: john@potato.growveg.org Cc: FreeBSD Filesystems <freebsd-fs@freebsd.org> Subject: Re: RAM and zfs and multiple disks Message-ID: <CAOjFWZ7YQpf_dQ5Ns=aW=bXgKjMoGbFe%2B41c1Em2r328kQ9dvQ@mail.gmail.com> In-Reply-To: <20131010170724.GA19751@potato.growveg.org> References: <20131010170724.GA19751@potato.growveg.org>
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On Thu, Oct 10, 2013 at 10:07 AM, John <freebsd-lists@potato.growveg.org>wr= ote: > I'd like to have zfs on my freebsd desktop. However, > this motherboard can take 8GB RAM, max. > > I'd like to get 2 x4Tb drives. Realistically, do I > need another motherboard? The primary reason to have ZFS > is to guard against bitrot > =E2=80=8B. > I ran ZFS on a 32-bit install of FreeBSD using a 3.0 GHz P4 with only 2 GB of RAM for several years. Started with 4x 160 GB drives in a raidz1 vdev and FreeBSD 8.x with / on UFS on a USB stick. Migrated to 2x 500 GB drives in a mirror vdev and FreeBSD 9.0, still with / on UFS on a USB stick. Migrated to 4x 1.0 TB drives in 2 mirror vdevs and PC-BSD 9.1, with ZFS-on-root (no USB sticks). At this point, I switched to a 64-bit install running on an Athlon-II CPU with 4 GB of RAM. Finally, migrated to "rolling-release" of PC-BSD (which shows as TruOS in uname) based on FreeBSD 9-STABLE (post 9.1) running on a Phenom-II X4 with 8 GB of RAM. Beauty of ZFS snapshots send/recv and boot environments is that I didn't lose any data during any of the migrations, and was able to reconfigure the pool a couple of times. And switch from 32-bit to 64-bit FreeBSD (only saved /home for that one). IOW, you don't need a tonne of RAM to run ZFS. You just need to spend some time tweaking ZFS-related tunables in /boot/loader.conf to guard against lockups due to lack of kmem (really only an issue on a 32-bit system due to kmem fragmentation). And, definitely do NOT enable dedupe on a system with multiple TB of storage unless you have 16+ GB of RAM! Compression is fine (running with lz4 on my home system now; originally was lzjb+gzip). --=20 Freddie Cash fjwcash@gmail.com
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