marko b wrote:
> At this point, this IS an academic exercize. I've tried to outline the
> motivations/justifications for wanting this particular functionality.
>
> I believe my architectural "why not?" and "is it possible?" question is
> sufficiently valid.
>
> Its not about disk cost. Its about being able to grow the pool easily, and
> without having to replace all the drives within the pool at the same time.
Then the best answer is mirroring.
To grow the size of the pool will require replacing all sides of the
mirror (I say all not both because you can have n disk mirrors). This
is done one disk at a time but the additional space doesn't appear until
all sides have been replaced.
For example:
Start out with 2 disks in the pool in a mirror:
time action config size
t0 create d1 mirror d2 min(d1,d2)
t1 add d1 mirror d2 min(d1,d2) + min(d3,d4)
d3 mirror d4
t2 replace d2 d1 mirror d2' min(d1,d2) + min(d3,d4)
d3 mirror d4
t3 replace d1 d1' mirror d2' min(d1,d2) + min(d3,d4)
d3 mirror d4
t4 reimport d1' mirror d2' min(d1'+d2') + min(d3,d4)
d3 mirror d4
Note that at this time you can only boot from simple (ie non striped)
mirrors.
--
Darren J Moffat
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