zfs discuss - Jan 2006 - Adding a mirror to an existing single disk zpool

Hello All,

  I''m transitioning data off my old UFS partitions onto ZFS.  I
don''t have a lot of duplicate space so I created a zpool,
rsync''ed the data from UFS to the ZFS mount and then repartitioned the
UFS drive to have partitions that match the cylinder count of the ZFS. The idea
here is that once the data is over I wipe out UFS and then attach that partition
to the zpool as a mirror.

  Problem is, I can''t see how to do this.  I can add the drive in a
concat fashion but can''t see how to add it as a mirror.  So how do I
turn a ZFS concat into a ZFS mirror without having to start from scratch?

benr.
This message posted from opensolaris.org

On Sun, Jan 29, 2006 at 04:15:23PM -0800, Ben Rockwood
wrote:
> Hello All,
> 
>   I''m transitioning data off my old UFS partitions onto ZFS.  I
don''t
>   have a lot of duplicate space so I created a zpool, rsync''ed the
>   data from UFS to the ZFS mount and then repartitioned the UFS drive
>   to have partitions that match the cylinder count of the ZFS. The
>   idea here is that once the data is over I wipe out UFS and then
>   attach that partition to the zpool as a mirror.
> 
>   Problem is, I can''t see how to do this.  I can add the drive in
a
>   concat fashion but can''t see how to add it as a mirror.  So how
do I
>   turn a ZFS concat into a ZFS mirror without having to start from
>   scratch? 
If you want to do something like:

	diskA -> mirror(diskA, diskB)

You can use the ''zpool attach'' command.

If, however, you want to do something like:

	diskA, diskB -> mirror(diskA, diskB)

Where ''A'' and ''B'' are in a dynamic stripe,
this isn''t currently
possible.  Once we support device removal, you will be able to remove
one drive or the other, and then re-attach it using ''zpool
attach''.

- Eric

--
Eric Schrock, Solaris Kernel Development       http://blogs.sun.com/eschrock

On Sun, Jan 29, 2006 at 04:15:23PM -0800, Ben Rockwood
wrote:
> Hello All,
> 
>   I''m transitioning data off my old UFS partitions onto ZFS.  I
don''t
>  have a lot of duplicate space so I created a zpool, rsync''ed the
>  data from UFS to the ZFS mount and then repartitioned the UFS drive
>  to have partitions that match the cylinder count of the ZFS. The
>  idea here is that once the data is over I wipe out UFS and then
>  attach that partition to the zpool as a mirror.
> 
>  Problem is, I can''t see how to do this.  I can add the drive in a
>  concat fashion but can''t see how to add it as a mirror.  So how
do
>  I turn a ZFS concat into a ZFS mirror without having to start from
>  scratch?
You want "zpool attach":

% zpool create foo c0t0d0s7
% zfs create foo/data
(copy data to /foo/data, freeing up c0t1d0s7 (or whatever))
% zpool attach foo c0t0d0s7 c0t1d0s7

which will start a scrub (to copy over the data on c0t0d0s7).  You can
watch the progress using "zpool status".  The end result will be:

foo
  mirror
    c0t0d0s7
    c0t1d0s7

Make sense?

Cheers,
- jonathan


-- 
Jonathan Adams, Solaris Kernel Development

Perfect, thanks guys!  I thought attach only worked for existing mirrors.  

benr.
This message posted from opensolaris.org

Just for the record and all, I thought I''d add some syntax for the
archives:

root at aeon storage2$ zpool status
  pool: storage2
 state: ONLINE
 scrub: none requested
config:

        NAME        STATE     READ WRITE CKSUM
        storage2    ONLINE       0     0     0
          c3d1s0    ONLINE       0     0     0

root at aeon storage2$ zpool attach -f storage2 c3d1s0 c1d0s0
root at aeon storage2$ zpool status
  pool: storage2
 state: ONLINE
status: One or more devices is currently being resilvered.  The pool will
        continue to function, possibly in a degraded state.
action: Wait for the resilver to complete.
 scrub: resilver in progress, 0.00% done, 161h26m to go
config:

        NAME        STATE     READ WRITE CKSUM
        storage2    ONLINE       0     0     0
          mirror    ONLINE       0     0     0
            c3d1s0  ONLINE       0     0     0
            c1d0s0  ONLINE       0     0     0  1.03M resilvered




The -f was only needed because the parition (or the at least the first couple
bits of it) I''m mirroring to previously had a UFS filesystem on it.

benr.
This message posted from opensolaris.org