[indiana-discuss] rpool and zfs usage

[Michael Hunter]

On Mon, 02 Jun 2008 14:07:14 -0700
Richard Elling <Richard.Elling at Sun.COM> wrote:

[...]
> > OK, got that the first time.  I understand why it is hard at boot.  But
> > are you saying it isn't a good idea in general or just at boot?  And if
> > in general then why?
> >   
> 
> It isn't a good idea in general, and it is especially a bad idea
> for boot.  Think of it this way, if you stripe disks together,
> then you get more space, but you also divide the reliability
> by the number of disks.  In other words, your new, striped
> configuration will be less than half as reliable as a simpler
> configuration.  If you can't boot, then you can't do anything,
> so it is important that boot devices are reliable.
[...]
> I can give you a gun and bullets, but if I could also
> prevent you from shooting a hole in your foot, wouldn't
> that be valuable?  Or is it more "pro-user" to allow you
> to shoot yourself?

I'm a cake and eat it guy.

[...]
> You can do installations with mirrored boot devices today using
> JumpStart.  The GUI installer folks are working on improving it,
> also.  But raidz for boot is much farther out.  Even if your BIOS
> supports it (methinks many won't) then the changes to grub will
> have to be made. That will take longer, even if demand exists.
> 
> In the bad old days when desktops had 40 MByte hard disks,
> optimizing for space while installing the OS was a much different
> task.  For today, when you can't purchase new storage anywhere
> near that size, the pain of squeezing an OS onto the disks has
> been eliminated.  Even the $269 Eee Box has an 80 GByte disk :-)
[...]

You havn't considered if there are multiple drives giving the option of
having the rpool be some part of the disk and leaving the rest to the
user to stripe, mirror, make multiples out of, etc.  As you said space
is cheap I don't mind rpool being a little fat (say 2x or 3x a liberal
estimation).  The way you've done it now if I want to use the space on
my other drive I'm going to have 2 pools anyways.  Why not allow them
to be used in a way that is more associated with how I administer and
want to use them?

			mph