aliasing (or renaming) kern.geom.debugflags
phk at phk.freebsd.dk
Sat Oct 8 08:18:56 UTC 2011
In message <alpine.BSF.2.00.1110071734140.4137 at wonkity.com>, Warren Block write
>Since we're talking about this, could you review the usage in the
>gmirror section of the Handbook GEOM chapter:
>Seems like that is a valid non-debugging use, to allow the last block to
gmirror and this procedure has several problems:
1. It steals the last sector on the disk. If that sector contained data
you lost them, with no notice. Most often it will not, particularly
on a freshly installed system, but it is still a bad thing.
2. The paritioning is not fixed up to record the stealing of this sector.
I wouldn't be surprised if this could cause confusion down the road.
3. In this case, writing only happens to a single sector, which we assume
is not going to be written by anybody else, so apart from #1 and #2
debugflags=16 does not cause any additional damage.
This is the kind of usage that makes me sad I ever added that option.
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG | TCP/IP since RFC 956
FreeBSD committer | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
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