Date: Fri, 08 Oct 2010 03:53:17 +0200 From: Adam Nowacki <nowak@xpam.de> To: freebsd-fs@freebsd.org Subject: Re: ZFS and Samsung Spinpoint F4 4K sector drive Message-ID: <4CAE798D.6040905@xpam.de> In-Reply-To: <4CAE6C3A.5070509@rcn.com> References: <4CAE6C3A.5070509@rcn.com>
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Nothing user friendly but if you're willing to modify sources and rebuild kernel there is a one line tweak. /usr/src/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/vdev_geom.c find: *ashift = highbit(MAX(pp->sectorsize, SPA_MINBLOCKSIZE)) - 1; and modify to something like: *ashift = highbit(MAX(MAX(4096, pp->sectorsize), SPA_MINBLOCKSIZE)) - 1; I'm using this for 3 months with 20 2TB 4kb sector WDC disks (in 2 raidz2 arrays of 10) without any issues. Writes go at 300MB/s. Gary Corcoran wrote: > I've tried to read up on the issue of using ZFS with 4K sector drives, > but haven't seen any definitive answers with regards to FreeBSD. > The Samsung Spinpoint F4 is their latest 2TB drive, which has 4K sectors > and "emulation", and no info on whether the emulation can be disabled. > But it is on sale for the next few days, and the price is very tempting. > > So I would like to ask: Can these 4K drives, emulating 512 byte sectors, > be successfully used with ZFS raidz via _some_ tweak, without getting a > major > slowdown? That is, is there some sysctl, some option to zpool create, or > anything else, that can cause a zpool which uses whole disks, to be aligned > to 4K sectors in FreeBSD? > > Thanks, > Gary > _______________________________________________ > freebsd-fs@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-fs > To unsubscribe, send any mail to "freebsd-fs-unsubscribe@freebsd.org" > >
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