I see, so no dedicated ZIL device in the end ? I could make a 15gb slice for the OS running UFS (I don't wanna risk losing the OS when manipulating ZFS, such as during upgrades), and a 25gb+ for L2ARC, depending on the disk.
I can't afford a *dedicated* drive for the cache though, not enough room in the machine. On 1/6/11 12:26 PM, Chris Forgeron wrote: > You know, these days I'm not as happy with SSD's for ZIL. I may blog about > some of the speed results I've been getting over the last 6mo-1yr that I've > been running them with ZFS. I think people should be using hardware RAM > drives. You can get old Gigabyte i-RAM drives with 4 gig of memory for the > cost of a 60 gig SSD, and it will trounce the SSD for speed. > > I'd put your SSD to L2ARC (cache). > > > -----Original Message----- > From: Damien Fleuriot [mailto:m...@my.gd] > Sent: Thursday, January 06, 2011 5:20 AM > To: Artem Belevich > Cc: Chris Forgeron; freebsd-stable@freebsd.org > Subject: Re: ZFS - moving from a zraid1 to zraid2 pool with 1.5tb disks > > You both make good points, thanks for the feedback :) > > I am more concerned about data protection than performance, so I suppose > raidz2 is the best choice I have with such a small scale setup. > > Now the question that remains is wether or not to use parts of the OS's ssd > for zil, cache, or both ? > > --- > Fleuriot Damien > > On 5 Jan 2011, at 23:12, Artem Belevich <fbsdl...@src.cx> wrote: > >> On Wed, Jan 5, 2011 at 1:55 PM, Damien Fleuriot <m...@my.gd> wrote: >>> Well actually... >>> >>> raidz2: >>> - 7x 1.5 tb = 10.5tb >>> - 2 parity drives >>> >>> raidz1: >>> - 3x 1.5 tb = 4.5 tb >>> - 4x 1.5 tb = 6 tb , total 10.5tb >>> - 2 parity drives in split thus different raidz1 arrays >>> >>> So really, in both cases 2 different parity drives and same storage... >> >> In second case you get better performance, but lose some data >> protection. It's still raidz1 and you can't guarantee functionality in >> all cases of two drives failing. If two drives fail in the same vdev, >> your entire pool will be gone. Granted, it's better than single-vdev >> raidz1, but it's *not* as good as raidz2. >> >> --Artem _______________________________________________ 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"
