ZFS v28 and zil_disable

Chris Forgeron cforgeron at acsi.ca
Sat Jan 1 00:01:23 UTC 2011

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. 

Christopher Forgeron, B.Sc., CCS, A+, N+ 
ACSI Consulting, Inc / Aardvark Computer Solutions, Inc.
email: chris at acsi.ca

2070 Oxford Street, Suite 100, Halifax NS B3L-2T2
Tel: 902-425-2686  Fax: 902-484-7909

-----Original Message-----
From: owner-freebsd-stable at freebsd.org [mailto:owner-freebsd-stable at freebsd.org] On Behalf Of Chris Forgeron
Sent: December-31-10 6:01 PM
To: freebsd-stable at 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-stable at freebsd.org [mailto:owner-freebsd-stable at freebsd.org] On Behalf Of Jean-Yves Avenard
Sent: December-27-10 1:31 AM
To: jhell
Cc: freebsd-stable at freebsd.org
Subject: Re: New ZFSv28 patchset for 8-STABLE: Kernel Panic

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 _______________________________________________
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