Update 8-01-2010:

Just learned that the Iscsi implementation embedded in ZFS is not so great and is replace by COMSTAR:

http://arc.opensolaris.org/caselog/PSARC/2010/006/20100106_james.dunham

I'll rewrite the document to use COMSTAR.

I wanted to backup my flakey MBP who has taken some abuse over the years on my Solaris ZFS based home server. I already have a ZFS pool up and running so I am skipping that part:

1. Creating a Zvol (200 Gb)
   

   # zfs create -V 200g datapool/mbp_iscsi_backup_zvol

2. Look at the zvol just created
   

   # zfs list
   [snip]
   datapool/mbp_iscsi_backup_zvol   200G   580G    16K  -
   [snip]
   

3. Make this zvol and Iscsi target
   

   # zfs shareiscsi=on datapool/mbp_iscsi_backup_zvol

4. See that its set properly
   

   # zfs get all datapool/mbp_iscsi_backup_zvol
   NAME                               PROPERTY               VALUE                  SOURCE
   datapool/mbp_iscsi_backup_zvol  type                   volume                 -
   datapool/mbp_iscsi_backup_zvol  creation               Tue Jan  5 13:05 2010  -
   datapool/mbp_iscsi_backup_zvol  used                   200G                   -
   datapool/mbp_iscsi_backup_zvol  available              580G                   -
   datapool/mbp_iscsi_backup_zvol  referenced             16K                    -
   datapool/mbp_iscsi_backup_zvol  compressratio          1.00x                  -
   datapool/mbp_iscsi_backup_zvol  reservation            none                   default
   datapool/mbp_iscsi_backup_zvol  volsize                200M                   -
   datapool/mbp_iscsi_backup_zvol  volblocksize           8K                     -
   datapool/mbp_iscsi_backup_zvol  checksum               on                     default
   datapool/mbp_iscsi_backup_zvol  compression            off                    default
   datapool/mbp_iscsi_backup_zvol  readonly               off                    default
   datapool/mbp_iscsi_backup_zvol  shareiscsi             on                     local
   datapool/mbp_iscsi_backup_zvol  copies                 1                      default
   datapool/mbp_iscsi_backup_zvol  refreservation         200G                   local
   datapool/mbp_iscsi_backup_zvol  primarycache           all                    default
   datapool/mbp_iscsi_backup_zvol  secondarycache         all                    default
   datapool/mbp_iscsi_backup_zvol  usedbysnapshots        0                      -
   datapool/mbp_iscsi_backup_zvol  usedbydataset          16K                    -
   datapool/mbp_iscsi_backup_zvol  usedbychildren         0                      -
   datapool/mbp_iscsi_backup_zvol  usedbyrefreservation   200G                   -
   datapool/mbp_iscsi_backup_zvol  com.sun:auto-snapshot  true                   inherited from datapool
   # 
   

5. Check the Iscsi deamon is running
   

   # ps -ef | grep scsi
       root  2838     1   0 16:13:14 ?           0:00 /usr/sbin/iscsitgtd
   #

6. If not start it
   

    # svcadm enable iscsitgt
    

7. Check if the Iscsi stuff is visible
   

   # iscsitadm list target
   Target: datapool/mbp_iscsi_backup_zvol
       iSCSI Name: iqn.1986-03.com.sun:02:afa0bb49-b575-c6eb-a95d-f4842e235472
       Connections: 0

8. Enable Iscsi discovery (not sure if this needs to be done)
   # iscsiadm modify discovery -s enable
   # iscsiadm list discovery
   \Discovery:
   	Static: enabled
   	Send Targets: disabled
   	iSNS: disabled
   # iscsitadm list target -v
   Target: datapool/mbp_iscsi_backup_zvol
       iSCSI Name: iqn.1986-03.com.sun:02:afa0bb49-b575-c6eb-a95d-f4842e235472
       Alias: datapool/mbp_iscsi_backup_zvol
       Connections: 0
       ACL list:
       TPGT list:
       LUN information:
           LUN: 0
               GUID: 0
               VID: SUN
               PID: SOLARIS
               Type: disk
               Size:  200M
               Backing store: /dev/zvol/rdsk/datapool/mbp_iscsi_backup_zvol
               Status: online
   #

9. Now the Mac OS C part (Mine was tested on Snow leopard):
   
   Download the free Iscsi software here: http://www.studionetworksolutions.com/products/product_detail.php?pi=11