good/best practices for gmirror and gjournal on a pair of disks?

[George Hartzell]

Adam McDougall writes:
 > George Hartzell wrote:
 > >[...]
 > >   - I've read in the gjournal man page that when it is "... configured
 > >     on top of gmirror(8) or graid3(8) providers, it also keeps them in
 > >     a consistent state..."  I've been trying to figure out if this
 > >     simply falls out of how gjournal works or if there's explicity
 > >     collusion with gmirror/graid3 but can't come up with a
 > >     satisfactory explanation.  Can someone walk me through it?
 > >
 > >     Since I'm only gjournal'ing a portion of the underlying gmirror
 > >     device I assume that I don't get this benefit?
 > >[...]
 > [...]
 > I decided to journal /usr /var /tmp and leave / as a standard UFS 
 > partition because it is so small, fsck doesn't take long anyway and 
 > hopefully doesn't get written to enough to cause damage by an abrupt 
 > reboot.  Because I'm not journaling the root partition, I chose to 
 > ignore the possibility of gjournal marking the mirror clean.  Sudden 
 > reboots don't happen enough on servers for me to care.  And all my 
 > servers got abruptly rebooted this sunday and they all came up fine :)
 > [...]

So you're confirming my belief that setting up gjournal on a
bsdlabel'ed partition of a gmirror does *not* provide the consistency
guarantee and that I should leave autosynchronization enabled.  Right?

g.