On Fri, Dec 31, 2010 at 08:01:17PM -0400, Chris Forgeron wrote: > Oh, and then I read what I post, and notice that the zil_disable parts are in > the .orig files, from the patch. :-) > > Oh well, I guess I'll just have to invest in a proper ZIL device. > > -----Original Message----- > From: owner-freebsd-sta...@freebsd.org > [mailto:owner-freebsd-sta...@freebsd.org] On Behalf Of Chris Forgeron > Sent: December-31-10 6:01 PM > To: freebsd-stable@freebsd.org > Subject: ZFS v28 and zil_disable > > BTW, I'm noticing the removal of vfs.zfs.zil_disable as well - It's not > listed as a sysctl when I check vfs.zfs, but I see it's still in the source > code; > > In usr/src/sys/cddl/ : > # grep -r zil_disable * > cddl/contrib/opensolaris/uts/common/fs/zfs/sys/zil.h.orig:extern int > zil_disable; > cddl/contrib/opensolaris/uts/common/fs/zfs/zil.c.orig:int zil_disable = 0; > /* disable intent logging */ > cddl/contrib/opensolaris/uts/common/fs/zfs/zil.c.orig:TUNABLE_INT("vfs.zfs.zil_disable", > &zil_disable); > cddl/contrib/opensolaris/uts/common/fs/zfs/zil.c.orig:SYSCTL_INT(_vfs_zfs, > OID_AUTO, zil_disable, CTLFLAG_RW, &zil_disable, 0, > cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vfsops.c.orig: if > (zil_disable) { > cddl/contrib/opensolaris/uts/common/fs/zfs/zvol.c.orig: if > (bp->bio_cmd == BIO_FLUSH && !zil_disable) > > > I know Sun was trying to move away from allowing people to disable the ZIL, > but was this by design in the FreeBSD port, or are we just missing some code > to link the sysctl up with the code to easily disable the ZIL? > > I'll try setting zil_disable=1 in the source tomorrow and recompile to see if > it works. It's such a huge speed increase for some operations (80MB/sec with > ZIL, 450 MB/sec without ZIL) that I still use zil_disable. > > I'll also have to check my 9.0-CUR v28 patch, although I assume it's the > same. > > > -----Original Message----- > From: owner-freebsd-sta...@freebsd.org > [mailto:owner-freebsd-sta...@freebsd.org] On Behalf Of Jean-Yves Avenard > Sent: December-27-10 1:31 AM > To: jhell > Cc: freebsd-stable@freebsd.org > Subject: Re: New ZFSv28 patchset for 8-STABLE: Kernel Panic > > Jean-Yves > PS: saving my 5MB files over the network , went from 40-55s with v15 to a > constant 16s with v28... I can't test with ZIL completely disabled , it seems > that vfs.zfs.zil_disable has been removed, and so did > vfs.zfs.write_limit_override
You shouldn't disable the ZIL[1], and you don't need a "proper ZIL device" for the ZIL to work. FreeBSD ZFS, like its Solaris counterpart, offers the ability for the ZIL to be associated with one or more dedicated devices[1]. These are referred to as "log" devices (not to be confused with "cache" devices). In the case you use a dedicated device for your ZIL, be aware that you should probably use two[2] devices (or if a single physical device, two slices) else risk data integrity problems. Switching over to a brief mention of "cache" devices, there is one case[3] of someone experiencing high CPU when either a USB flash drive or an SSD drive[4], where rebooting the system apparently solved the problem (we do not know if this was the case permanently or temporarily). [1]: http://www.solarisinternals.com/wiki/index.php/ZFS_Evil_Tuning_Guide#Disabling_the_ZIL_.28Don.27t.29 [2]: http://forums.freebsd.org/showthread.php?t=18221 [3]: http://lists.freebsd.org/pipermail/freebsd-stable/2010-November/060014.html [4]: http://lists.freebsd.org/pipermail/freebsd-stable/2010-November/060076.html -- | Jeremy Chadwick j...@parodius.com | | Parodius Networking http://www.parodius.com/ | | UNIX Systems Administrator Mountain View, CA, USA | | Making life hard for others since 1977. PGP 4BD6C0CB | _______________________________________________ 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"
