[OpenIndiana-discuss] ZFS 0+1 across disparate drives

[Michelle]

You're perfectly correct. After I put the command together, I realised
that I'd made a mistake in putting raidz in there. 

The balance of partitions and using those instead of drives... I hadn't
thought of that. I guess I'm just too used to thinking at the drive
level for ZFS.



On Wed, 2021-12-01 at 15:33 +0000, James wrote:
> On 01/12/2021 11:55, Michelle wrote:
> > I have closing on 12TB of data so even the 10 won't be enough to
> > back
> > everything up, but this is as much for the exercise of doing it, as
> > achieving anything solid. It won't be under pressure, but I'd
> > rather
> > push the envelope and see what I can do.
> > 
> > So how would the command go?
> > 
> > zpool create tank raidz mirror drive1 drive2 mirror drive3 drive4
> > drive5
> > 
> > ...which is where I come unstuck with the 2TB drive in the mix.
> 
> You are right to be stuck as ZFS can not make a mirror of raid0 in
> one 
> command, zfs is wanting raid0 of mirrors which you can't get to 10TB 
> because you don't have pairs.  You can pair the 4&6 and raid0 with
> 4&4 
> and get 8TB of continuous pool.
> 
> Partition the 6 into 4 and 2, then you have pairs for raid0 of
> mirrors. 
> Loose the 6TB and you loose 1/2 of 2 mirrors but you are better off
> than 
> loosing 1/2 the entire mirror with mirror of raid0.  10TB using all
> devices.
> 
> Try making 2 raid0 pools 2+4+4 and 4+6, create volumes on those
> pools 
> and use to make a mirror, /dev/zvol/dsk/etc...  Untested and I can't
> see 
> it being better.
> 
> Use raidz1 of 4, 4, 4, and 6 = 12TB.  This ignore 2TB of the 6 and
> you 
> get a bonus doorstop by not using the 2TB.  3+1 is not a preferred 
> arrangement.
> 
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