Re: What's the status of vinum?

On Mon, 16 Aug 2004 02:23:03 -0700, "Darren Pilgrim" <dmp_at_bitfreak.org>
wrote:

> I'm currently doing a vinum RAID 1 on a box that runs RELENG_4_8.  For
> what I do, at least, RELENG_5_2 "feels worthy" of a production box and
> I'd really like to take advantage of some features 4.x doesn't have.
> The threads on vinum/gvinum have me wondering if I should hold off a
> bit.  What's the current condition of gvinum?  How well does
> vinum/gvinum work in RELENG_5_2?  What are the features not yet
> implemented in gvinum?  My eyeballs didn't capture any URLs for a
> status
> page, but if someone can point me at one, that would be great.

I am using vinum in a RAID 1 root-on-vinum setup on a RELENG_5_2 system
(which started life as a RELENG_5_1 vinum setup that was upgraded at
various times).  It works the same as my RELENG_4 system except for
swap.  That stopped working after FreeBSD 5.1.  If you want to retain
mirrored swap for RELENG_5_2 you basically have to use a hack workaround
like using your old swap partition as a UFS filesystem and then swapping
to a large file situated on it.  (Alternatively, you can elect to have
un-mirrored swap.)

I am also using gvinum in a RAID 1 root-on-gvinum setup on -CURRENT
(last built circa 5th August).  The gvinum layout is actually copied
from the above RELENG_5_2 system, and uses the same model of disk
drive.  Fortunately, swap works properly in this gvinum setup, so no
need for those RELENG_5_2 hacks.  I actually created the "gvinum"
configuration a while ago using vinum because gvinum complained a little
about the vinum configuration file I copied over and used. 
(Specifically, it didn't like the "setupstate" option for my volumes.) 
I don't know what other functionality the gvinum parser lacks, but I
believe it has all the basic necessities.  I haven't experimented very
much with gvinum, but I have to say in day-to-day use that geom_vinum
has been rock solid (surviving the era of PREEMPTION-induced freezes and
all:).

The only major omission I've noticed in the geom_vinum implementation is
round-robin access to plexes in a RAID 1 volume.  Right now, the
behaviour is like "prefer <someplex>" in that all reads go to a single
plex of a volume.  Lukas says he intends to address this in the future. 
So, right now, gvinum may give less throughput than vinum used to.

Given the lack of vinum swap support on RELENG_5_2, you might want to
hold on until 5.3 is released.  AFAIK, gvinum is not available in
RELENG_5_2.

If you are just interested in a mirrored setup, there is also now a
geom_mirror feature in -CURRENT that might fulfil your needs.  I've not
used it, so can't really comment on it.  I'm guessing that it will also
appear in FreeBSD 5.3.

Cheers,

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

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