On Mon, Jun 15, 2009 at 8:47 AM, George Hartzell <hartz...@alerce.com>wrote:
> Freddie Cash writes: > > On Sun, Jun 14, 2009 at 9:17 AM, Dan Naumov <dan.nau...@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? > Going back through some old threads, it seems that I was mistaken, and it's only on Solaris that disk cache is disabled for vdevs created from partitions. 3 cheers for GEOM. :) -- Freddie Cash fjwc...@gmail.com _______________________________________________ freebsd-stable@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-stable To unsubscribe, send any mail to "freebsd-stable-unsubscr...@freebsd.org"
