Re: Vinum status

On Thu, 2004-07-29 at 15:57, Lukas Ertl wrote:
> On Thu, 29 Jul 2004, Paul Mather wrote:
> 
> > Does this imply that root-on-gvinum is working now?  Last time I tried
> > it (shortly after gvinum was committed to the tree), it worked except
> > that only half of the drives, plexes, and volumes in my Vinum RAID 1
> > mirror were detected when the gvinum module read the configuration from
> > the drives during boot.
> 
> I still didn't have a chance to build a root-on-gvinum setup, but I'd be 
> happy if you could test it.  It's quite likely that the errors were 
> related.

I rebuilt my kernel+world as part of the GCC 3.4.2 import, and
re-attached my two root-on-vinum test drives.  I dumped over the current
system to the vinum volumes and edited /etc/fstab for an all-vinum
setup.

I'm happy to report that the current geom_vinum kernel module
successfully detects all plexes during boot when loaded from
/boot/loader.conf.  So, I now have a working root-on-gvinum setup
running (including swap-on-gvinum).  Thanks!!

My only question is that although writes go to both disks in my mirrored
setup, reads are only done from one disk of the mirror.  In my case, all
reads are always to drive ad2 of my ad0+ad2 mirror.  This implies to me
a default "readpol prefer <someplex>" on my defined volumes rather than
the "readpol round" that appears to be the default under vinum.  (At
least on my 4.10-STABLE system, both drives are used for reads, implying
a "readpol round" default behaviour.)

Does gvinum support "readpol round" or is it just that its default
differs from the old vinum?  If the latter, is there a way to change the
read policy on a volume without deleting the old volume or otherwise
destroying its contents?  The vinum configuration I'm using is an exact
duplicate of a 5.1-RELEASE system I created.  That system (since
upgraded to 5.2.1-RELEASE-p9) also sends reads to both drives using
vinum.

Again, great job on the gvinum work!  (Will you link the kernel module
into the normal kernel build?  I forgot it wasn't the first time I built
my kernel, and had to go back and build manually the geom_vinum module
when I couldn't find it to load when at the boot loader prompt.  Ditto
for including gvinum in the regular userland build process.)

Cheers,

Paul.
-- 
e-mail: paul_at_gromit.dlib.vt.edu

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