vinum raid5: newfs throws an error

[Markus Hoenicka]

Greg 'groggy' Lehey writes:
 > There was once an error in the stripe size calculations that meant
 > that there were holes in the plexes.  Maybe it's still there (old
 > Vinum is not being maintained).  But you should have seen that in the
 > console messages at create time.
 > 
 > > Vinum reports the disk sizes as 17500MB (da1) and 17359MB (da2,
 > > da3). The raid5 volume and plex have a size of 33GB.
 > 
 > This looks like the kind of scenario where that could happen.  Try
 > this:
 > 
 > 1.  First, find a better stripe size.  It shouldn't be a power of 2,
 >     but it should be a multiple of 16 kB.  I'd recommend 496 kB.  This
 >     won't fix the problem, but it's something you should do anyway
 > 
 > 2.  Calculate the length of an exact number of stripes, and create the
 >     subdisks in that length.  Try again and see what happens.
 > 
 > 3.  Use gvinum instead of vinum and try both ways.
 > 

Ok, I decreased the stripe size to 496, regardless of whether it has
anything to do with my problem. Next I set the subdisk length to
17359m on all disks, and things started to work ok. No more newfs
errors here.

Before doing this I also had a brief encounter with gvinum. There is
no manpage in 5.3BETA7, so I assumed it groks the same config files as
vinum. However, this did not do me any good as it simply rebooted the
box. I guess gvinum works better in RELEASE.

Thanks a lot for your help.

Markus

-- 
Markus Hoenicka
markus.hoenicka at cats.de
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