Adding more disk's on ZFS array

[Zaphod Beeblebrox]

On Sat, Jun 27, 2009 at 6:27 PM, Dan Naumov <dan.naumov at gmail.com> wrote:

> On Sun, Jun 28, 2009 at 12:58 AM, Rafael Caesar
> Lenzi<rc_lenzi at yahoo.com.br> wrote:
> >
> > Hi!
> > How i can add more disks on ZFS raid0 or raid5 array?
> >
> > Thanks!
> > Rafael Lenzi
>
> raid0 (stripe): zpool add POOLNAME DEVICENAME
> raid5 (raidz): you can't
>

Not entirely true. For a RAID 0 stripe, yes, you can just add a disk.  Be
clear, however, that existing data is not striped to that disk, but the new
disk is used for new data.

For RAID 5 (raidz), you have two options.  You can replace each disk, in
turn, with a larger disk and heal the array each time.  I did this, for
instance, to move from 5 750G drives to 5 1.5T drives.  Another option is to
add another bunch of RAID 5 drives.  If you have 5 existing drives RAID 5,
you can add another set of dries with zpool add.  According to
documentation, each pool should be of the same RAID type.  It doesn't,
however, specify that each set of RAID 5 disks should have the same number
of disks in it.  This seems to mean that you could add a set of 3 disks
(raid 5) to an existing raid 5 array with 5 disks.