[OpenIndiana-discuss] Intruducing a new pair of rpool mirror discs

[Harry Putnam]

"Coalson, Timothy Scott (S&T-Student)" <tsc5yc at mst.edu> writes:

> Having (much) less than 300GB of data doesn't mean none of it is
> written past the 300GB mark, and I believe mirror vdevs use the same
> offset in each component device for the mirror copies.  Even for
> relatively simple fs-on-softraid setups, you have to use specialized
> tools to move data out of the end of the partition and update its new
> location in all other filesystem structures, and these usually operate
> while the filesystem is unmounted.  I don't know if such tools exist
> for zfs.  Doing this with the filesystem mounted would need at least
> block pointer rewrite (which has been on the wishlist for a long
> time).  I expect zpool will just tell you it can't be attached as a
> mirror because it is the wrong size, no matter what other options used
> (take care not to accidentally use "add").
>
> However, if you made a new pool from scratch and used zfs send and
> receive, and then did whatever to get the bootloader squared away, you
> could then swap to the new disks.

Ugh ... thanks for good info.. the option above sounds like the way to
go. 

> SSDs would be a lot more noticeable upgrade than velociraptors, and
> run cooler.  I haven't tried setting up overprovisioning on zfs boot
> drives yet, though.

I have to be careful what I try to install on this old HP wx 8600.
Maybe SSDs would be fine,  but, for example, I bought 2 3tb discs and
installed them ... only to find the HP xw8600 could not run 3 TB
disks.

Thanks for the good input.