gvinum raid10 stale

[Dimitri Aivaliotis]

Hi Rick,

On Mon, Dec 22, 2008 at 9:03 PM, Rick C. Petty
<rick-freebsd2008 at kiwi-computer.com> wrote:
> On Mon, Dec 22, 2008 at 05:20:36PM +0100, Dimitri Aivaliotis wrote:
>>
>
> This is a mirror of stripes, but I'm not really sure what you gain by
> staggering across all the drives like that.  Are you doing this for some
> performance gain?  If you're really using five disks, you may wish to
> consider raid5.  Otherwise, this looks like a mirror of stripes across five
> disks.  Much prettier than what you posted originally.

OK, so this IS expandable.  That's good news.

My real-life situation is going from 2 to 4 disks, so RAID5 is not an
option here.


> Are you trying to add mirrors or did you want to increase your volume size?

I want to increase volume size.

> You could increase the volume size, but the underlying filesystem would
> need to be resized.  I'm not sure if gvinum lets you increase the volume
> size.  If you just want to add another striped mirror:
>
> plex org striped 512k volume raid10
>  sd length 102480k drive f
>  sd length 102480k drive g
>  sd length 102480k drive h
>  sd length 102480k drive i
>  sd length 102480k drive j

Ok, so this would just increase resiliency, without increasing volume size?

Unfortunately so:

(I had to change the plex line because it gave an error: invalid plex
definition '   plex org striped 512k volume raid10')

plex name raid10.p2 org striped 512k vol raid10
<subdisks>
plex name raid10.p3 org striped 512k vol raid10
<subdisks>

# gvinum lp -v
4 plexes:
Plex raid10.p3: Size:   146767085568 bytes (139968 MB)
                Subdisks:       32
                State: down
                Organization: striped   Stripe size: 512 kB
                Part of volume raid10
Plex raid10.p2: Size:   146767085568 bytes (139968 MB)
                Subdisks:       32
                State: down
                Organization: striped   Stripe size: 512 kB
                Part of volume raid10
Plex raid10.p0: Size:   146767085568 bytes (139968 MB)
                Subdisks:       32
                State: down
                Organization: striped   Stripe size: 512 kB
                Part of volume raid10
Plex raid10.p1: Size:   146767085568 bytes (139968 MB)
                Subdisks:       32
                State: up
                Organization: striped   Stripe size: 512 kB
                Part of volume raid10


But this is not what I'm looking to do, as I'd like to increase volume size.

>> Thanks for your patience with me here.  I'm trying to understand how
>> this should work.
>
> No problem.  I would still recommend getting rid of the stripes to reduce
> your complexity and simplify future additions, but that's my personal
> preference.

I agree.  If I'm going to be reconfiguring the disks anyways, how can
I setup a configuration where I can grow a volume that starts out as a
2-disk mirror?  I've tried a few different configurations on a test
server now, but nothing seems to allow me to access the files on the
current volume in its expanded state.

- Dimitri