RAIDZ Expansion - 4k Alignment

[Con7undrum]

Situation -
4x 2GB Disks in RAIDZ
2x SSD ZIL Mirrored

I'd like to expand the RAIDZ Pool by one disk but am not sure how I align the single disk to add it to the pool. I aligned the existing pool by creating the nops, exporting the pool, destroying the nops and then reimporting the pool (rough description...it's been a while and I believe that's what I ended up doing). Any ideas as to how I can maintain the 4k alignment and expand the pool? am I over thinking it?

[ChriZathens]

If you add one single drive to your pool, you will lose redundancy.

[Con7undrum]

If I added 2 disks then?

[b0ssman]

yes you an create a mirror vdev and add it to the pool.

if one of the vdevs dies you loose the entire pool.

this will happen if 2 drives in the raidz1 die or 2 drives in the mirror.

[raulfg3]

If I added 2 disks then?

Please read this powerpoint, because how to expand is very well explained: http://forums.freenas.org/index.php?thr ... oobs.7775/

[crowi]

Basically you do the same:
1) create the drives (gpart create -s gpt adaX (for your two (!) drives))
2) create the 4k partitions/format with zfs and 4k
3) create gnops of both drives with the 4096 stripeset
4) create a mirror vdev and add it to the pool
5) export the pool
6) destroy the *.nops
7) import the pool