[Dovecot] Fix? available for mmap on FreeBSD zfs (corrupted index files)

[Adam McDougall]

Just as a heads up since some dovecot users do use ZFS, pjd recently 
posted a patch to upgrade ZFS in 8-current from v6 to v11 (latest from
opensolaris).  Its reported to fix a number of problems, and add new 
features.  The patch does not apply to 7, that won't be available for
a while apparently, but they are looking for feedback on the fs or current
mailing lists to encourage sooner integration (possibly by 7.1).  

Quick instructions:
fetch http://people.freebsd.org/~pjd/patches/zfs_20080727.patch.bz2
bunzip2 zfs_20080727.patch.bz2
cd /usr/src/
patch -p0 < /path/to/zfs_20080727.patch
do a FULL upgrade of world/kernel.

kmem tweaks may still be needed but its a little more resilient than
before, also 8-current now lets you configure a larger kmem than the 
previous ~1.8G limit.  It is recommended to remove other tweaks from
loader.conf such as zil_disable, etc and see how it does.  

I've upgraded my laptop and so far so good, but I don't have dovecot 
on any systems with ZFS so I can't test that aspect.

On Fri, Apr 04, 2008 at 02:06:40PM -0400, Dillon Kass wrote:

  Hi, I've applied this patch to my 7-STABLE box and it doesn't help with 
  the corrupted dovecot index files.
  
  Anyone using dovecot with ZFS on FreeBSD should use mmap_disable = yes 
  in their dovecot.conf
  
  Cheers,
  Dillon
  
  Adam McDougall wrote:
  > Saw this just come through for 8-current,  7-stable ought to have it 
  > in a week or so.  I have not encountered the problem so I would not be 
  > able to judge if this fixes it.
  > Patch here: 
  > http://www.freebsd.org/cgi/cvsweb.cgi/src/sys/contrib/opensolaris/uts/common/fs/zfs/zfs_vnops.c.diff?r1=1.27;r2=1.28 
  >
  >
  >
  > pjd         2008-03-15 23:23:04 UTC
  >
  >  FreeBSD src repository
  >
  >  Modified files:
  >    sys/contrib/opensolaris/uts/common/fs/zfs zfs_vnops.c  Log:
  >  Fix mmap(2) on ZFS after some changes in VM subsystem.
  >  
  >  Submitted by:   alc
  >  Reported by:    kris (originally) and many others
  >  Tested with:    fsx
  >  MFC after:      1 week
  >  
  >  Revision  Changes    Path
  >  1.28      +4 -0      
  > src/sys/contrib/opensolaris/uts/common/fs/zfs/zfs_vnops.c
  >