Does this disk/filesystem layout look sane to you?
hartzell at alerce.com
Mon Jun 15 15:47:46 UTC 2009
Freddie Cash writes:
> On Sun, Jun 14, 2009 at 9:17 AM, Dan Naumov <dan.naumov at gmail.com> wrote:
> > I just wanted to have an extra pair (or a dozen) of eyes look this
> > configuration over before I commit to it (tested it in VMWare just in
> > case, it works, so I am considering doing this on real hardware soon).
> > I drew a nice diagram: http://www.pastebin.ca/1460089 Since it doesnt
> > show on the diagram, let me clarify that the geom mirror consumers as
> > well as the vdevz for ZFS RAIDZ are going to be partitions (raw disk
> > => full disk slice => swap partition | mirror provider partition | zfs
> > vdev partition | unused.
> I don't know for sure if it's the same on FreeBSD, but on Solaris, ZFS will
> disable the onboard disk cache if the vdevs are not whole disks. IOW, if
> you use slices, partitions, or files, the onboard disk cache is disabled.
> This can lead to poor write performance.
> Unless you can use one of the ZFS-on-root facilities, I'd look into getting
> a couple of CompactFlash or USB sticks to use for the gmirror for / and /usr
> (put the rest on ZFS). Then you can dedicate the entirety of all 5 drives
> to ZFS.
Even if you use do a bootable ZFS on root, you'll end up with a couple
of gpt partitions (boot code, swap, then root) and therefor
constructing your ZFS file system from a partition.
Pawel said, back on April 6, 2007,
"We support cache flushing operations on any GEOM provider (disk,
partition, slice, anything disk-like), so bascially currently I
treat everything as a whole disk [...]"
Does anyone know for sure if we disable caching for partitions?
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