zfs discuss - Jun 2009 - Migration: 1 x 160GB IDE boot drive ---> 2 x 30GB SATA SSDs

Hi,

I have OpenSolaris 2009.06 currently installed on a 160 GB IDE drive.
I want to replace this with a 2-way mirror 30 GB SATA SSD boot setup.

I found these 2 threads which seem to answer some questions I had, but I still
have some questions.
http://opensolaris.org/jive/thread.jspa?messageID=386577
http://opensolaris.org/jive/thread.jspa?threadID=104656

FIRST QUESTION:
Although, it seems possible to add a drive to form a mirror for the ZFS boot
pool ''rpool'', the main problem I see is that in my case, I
would be attempting to form a mirror using a smaller drive (30GB) than the
initial 160GB drive.
Is there an easy solution to this problem, or would it be simpler to just do a
reinstall of OpenSolaris 2009.06 onto 2 brand new 30GB SSDs? I have the option
of the fresh install, as I haven''t invested much time in configuring
this OS2009.06 boot environment yet.

SECOND QUESTION:
I also want the possibility to have multiple boot environments within
OpenSolaris 2009.06 to allow easy rollback to a working boot environment in case
of an IPS update problem. I presume this will not cause any additional
complications?


THIRD QUESTION:
This is for a home fileserver so I don''t want to spend too much, but
does anyone see any problem with having the OS installed on MLC SSDs, which are
cheaper than SLC SSDs. I''m thinking here specifically about wearing out
the SSD if the OS does too many writes to the SSDs.

I agree SSDs are a bit overkill, and using standard spinning metal would be
cheaper, but the case is vibrating like crazy as I ran out of drive slots and
had to use non-grommeted attachments for the boot drive. But the SSDs should be
silent and should certainly speed up boot and shutdown times dramatically :)

Thanks,
Simon

http://breden.org.uk/2008/03/02/a-home-fileserver-using-zfs/
-- 
This message posted from opensolaris.org

On Wed, Jun 24, 2009 at 6:32 PM, Simon Breden<no-reply at opensolaris.org>
wrote:
> FIRST QUESTION:
> Although, it seems possible to add a drive to form a mirror for the ZFS
boot pool ''rpool'', the main problem I see is that in my case,
I would be attempting to form a mirror using a smaller drive (30GB) than the
initial 160GB drive.
> Is there an easy solution to this problem, or would it be simpler to just
do a reinstall of OpenSolaris 2009.06 onto 2 brand new 30GB SSDs? I have the
option of the fresh install, as I haven''t invested much time in
configuring this OS2009.06 boot environment yet.
Depends on how you define "easy". Due to the smaller new drive, you
can''t use "zpool replace".
Some people will find this easy enough :
http://www.solarisinternals.com/wiki/index.php/ZFS_Troubleshooting_Guide#ZFS_Root_Pool_Recovery
Others might find it''s too complicated, and opt for reinstall plus
"zpool attach"
>
> SECOND QUESTION:
> I also want the possibility to have multiple boot environments within
OpenSolaris 2009.06 to allow easy rollback to a working boot environment in case
of an IPS update problem. I presume this will not cause any additional
complications?
Correct.
> THIRD QUESTION:
> This is for a home fileserver so I don''t want to spend too much,
but does anyone see any problem with having the OS installed on MLC SSDs, which
are cheaper than SLC SSDs. I''m thinking here specifically about wearing
out the SSD if the OS does too many writes to the SSDs.
zfs is SSD-friendly due to it''s copy-on-write nature. Having a mirror
also provide additional level of protection.

-- 
Fajar