gjournal: journaled slices vs. journaled partitions

[Volodymyr Kostyrko]

2008/11/4 Gabriel Lavoie <glavoie at gmail.com>:
> When building this setup I got one big problem. If the root filesystem (/)
> was on a gjournal provider, an unclean shutdown when data was being written
> on the disk rendered the system completely unbootable. I got this message:
>
> GEOM_MIRROR: Device mirror/gm launched (2/2)
> GEOM_JOURNAL: Journal 3672855181: mirror/gma contains data.
> GEOM_JOURNAL: Journal 3672855181: mirror/gma contains journal.
> GEOM_JOURNAL: Journal 3868799910: mirror/gmd contains data.
>
> GEOM_JOURNAL: Journal 3868799910: mirror/gmd contains journal.
> GEOM_JOURNAL: Journal mirror/gmd consistent.

Just one thing - you have two separate journaled partitions, one
journal per one partition.

> Trying to mount root from ufs:/dev/mirror/gm.journal
>
> Manual root filesystem specification:
>     <fstype>:<device>  Mount <device> using filesystem <fstype>
>
>                                            eg. ufs:da0s1a
>     ?                             List valid disk boot devices
>     <empty line>          Abort manual input
>
>
> mountroot> ?
>
> List of GEOM managed disk devices:
>
>      mirror/gmd.journal mirror/gmd mirror/gmc mirror/gma mirror/gm ad10s1c
> ad10s1b ad8s1c ad8s1b ad10s2 ad10s1 ad8s1 ad10 ad8 acd0
>
> As you can see, in the proposed list of disk devices devices to boot on,
> "mirror/gm.journala" is absent. As I and Ivan Voras, that I contacted about
> this problem, found, the GEOM_JOURNAL thread that is supposed to mark the
> journal consistent takes too much time to do it with the root filesystem's
> provider and the kernel try to mount a device that doesn't yet exist. A bug
> report has been opened about this problem. For my final setup I decided to
> put the root filesystem on a separate mirrorred slice of 1GB. Since this
> slice isn't often written on, not many rebuilds should occur in case of
> power failure. And I made my "power failure" test by hitting the reset
> button while writing data on this filesystem and the rebuild on 1GB doesn't
> takes too much time (at most 20-30 seconds).

Good to hear it, i've fallen for that too, but the machine isn't
powercycled at all and runs on guaranteed power. I had the similar
problems with described setup on virtual test machine too, yet
entering anything at mountroot> prompt gave gjournal a chance to keep
up and needed partition comes up eventually... I didn't reported that,
thought it was a virtual machine issue.

> Now I have the question. Why the "load" algorith wasn't recommended? Is it
> fixed in 7.0-RELEASE-p5?

Nope...

http://www.freebsd.org/cgi/query-pr.cgi?pr=113885

-- 
Sphinx of black quartz judge my vow.