Figured out the Log file and this is what I got.
Sep 21 05:39:05 freenas proftpd[2090]: 127.0.0.1 - ProFTPD 1.3.3g (maint) (built Thu Jul 19 2012 19:57:37 UTC) standalone mode STARTUP
Sep 21 05:39:13 freenas ntpd[1591]: time reset +0.440821 s
Sep 21 05:41:50 freenas root: ZFS: vdev I/O failure, zpool=RAIDZ path=/dev/gptid/cc25493d-f9c6-11e1-beef-002215766855 offset=270336 size=8192 error=6
Sep 21 05:41:50 freenas kernel: (ada7:ahcich7:0:0:0): lost device
Sep 21 05:41:50 freenas root: ZFS: vdev I/O failure, zpool=RAIDZ path=/dev/gptid/cc25493d-f9c6-11e1-beef-002215766855 offset=2998444761088 size=8192 error=6
Sep 21 05:41:50 freenas root: ZFS: vdev I/O failure, zpool=RAIDZ path=/dev/gptid/cc25493d-f9c6-11e1-beef-002215766855 offset=2998445023232 size=8192 error=6
Sep 21 05:42:42 freenas manage.py: [middleware.zfs:478] It should be a valid device: gptid/cc25493d-f9c6-11e1-beef-002215766855
Sep 21 05:43:03 freenas kernel: swap_pager: I/O error - pageout failed; blkno 3670025,size 12288, error 6
Sep 21 05:43:03 freenas kernel: swap_pager: I/O error - pageout failed; blkno 3670028,size 65536, error 6
Sep 21 05:43:03 freenas kernel: swap_pager: I/O error - pageout failed; blkno 3670055,size 65536, error 6
Sep 21 05:43:03 freenas kernel: swap_pager: I/O error - pageout failed; blkno 3670044,size 4096, error 6
Sep 21 05:43:05 freenas kernel: swap_pager: I/O error - pageout failed; blkno 3670071,size 65536, error 6
Sep 21 05:43:05 freenas kernel: swap_pager: I/O error - pageout failed; blkno 3670045,size 4096, error 6
Sep 21 05:43:05 freenas kernel: swap_pager: I/O error - pageout failed; blkno 3670046,size 4096, error 6
Sep 21 05:43:05 freenas kernel: swap_pager: I/O error - pageout failed; blkno 3670047,size 4096, error 6
Sep 21 05:43:07 freenas kernel: swap_pager: I/O error - pageout failed; blkno 3670048,size 8192, error 6
Sep 21 05:43:07 freenas kernel: swap_pager: I/O error - pageout failed; blkno 3670087,size 65536, error 6
Sep 21 05:43:07 freenas kernel: swap_pager: I/O error - pageout failed; blkno 3670103,size 65536, error 6
Sep 21 05:43:07 freenas kernel: swap_pager: I/O error - pageout failed; blkno 3670119,size 65536, error 6
Sep 21 05:43:08 freenas kernel: swap_pager: I/O error - pageout failed; blkno 3670135,size 65536, error 6
Sep 21 05:43:09 freenas kernel: swap_pager: I/O error - pageout failed; blkno 3670151,size 28672, error 6
Sep 21 05:43:09 freenas kernel: swap_pager: I/O error - pageout failed; blkno 3670158,size 65536, error 6
Sep 21 05:43:09 freenas kernel: swap_pager: I/O error - pageout failed; blkno 3670183,size 65536, error 6
Sep 21 05:43:10 freenas kernel: swap_pager: I/O error - pageout failed; blkno 3670199,size 65536, error 6
Sep 21 05:43:10 freenas kernel: swap_pager: I/O error - pageout failed; blkno 3670050,size 4096, error 6
Sep 21 05:43:10 freenas kernel: swap_pager: I/O error - pageout failed; blkno 3670174,size 24576, error 6
Sep 21 05:44:16 freenas manage.py: [middleware.zfs:478] It should be a valid device: gptid/cc25493d-f9c6-11e1-beef-002215766855
Sep 21 05:44:51 freenas last message repeated 2 times
Sep 21 05:46:29 freenas root: ZFS: vdev I/O failure, zpool=RAIDZ path=/dev/gptid/cbad4bef-f9c6-11e1-beef-002215766855 offset=270336 size=8192 error=6
Sep 21 05:46:29 freenas kernel: (ada6:ahcich6:0:0:0): lost device
Sep 21 05:46:29 freenas root: ZFS: vdev I/O failure, zpool=RAIDZ path=/dev/gptid/cbad4bef-f9c6-11e1-beef-002215766855 offset=2998444761088 size=8192 error=6
Sep 21 05:46:29 freenas root: ZFS: vdev I/O failure, zpool=RAIDZ path=/dev/gptid/cbad4bef-f9c6-11e1-beef-002215766855 offset=2998445023232 size=8192 error=6
Sep 21 05:46:29 freenas root: ZFS: vdev I/O failure, zpool=RAIDZ path= offset= size= error=
Sep 21 05:46:30 freenas last message repeated 82 times
Sep 21 05:46:31 freenas root: ZFS: vdev I/O failure, zpool=RAIDZ path= offset=828460187648 size=6144 error=6
Sep 21 05:46:31 freenas root: ZFS: vdev I/O failure, zpool=RAIDZ path= offset= size= error=
Sep 21 05:46:31 freenas last message repeated 29 times
Sep 21 05:46:31 freenas root: ZFS: vdev I/O failure, zpool=RAIDZ path= offset=3299357638656 size=6144 error=6
Sep 21 05:46:31 freenas root: ZFS: vdev I/O failure, zpool=RAIDZ path= offset= size= error=
Sep 21 05:46:31 freenas last message repeated 34 times
Sep 21 05:46:31 freenas root: ZFS: vdev I/O failure, zpool=RAIDZ path= offset=828460187648 size=6144 error=6
Sep 21 05:46:31 freenas root: ZFS: vdev I/O failure, zpool=RAIDZ path= offset=3299357638656 size=6144 error=6
Sep 21 05:46:31 freenas root: ZFS: zpool I/O failure, zpool=RAIDZ error=6
Sep 21 05:46:31 freenas root: ZFS: vdev I/O failure, zpool=RAIDZ path= offset= size= error=
Sep 21 05:46:55 freenas root: ZFS: zpool I/O failure, zpool=RAIDZ error=6
Sep 21 05:46:55 freenas root: ZFS: zpool I/O failure, zpool=RAIDZ error=28
Sep 21 05:46:55 freenas root: ZFS: zpool I/O failure, zpool=RAIDZ error=6
Sep 21 05:46:55 freenas root: ZFS: zpool I/O failure, zpool=RAIDZ error=6
Sep 21 05:46:55 freenas root: ZFS: zpool I/O failure, zpool=RAIDZ error=28
Sep 21 05:46:55 freenas last message repeated 2 times
Sep 21 05:46:55 freenas root: ZFS: vdev I/O failure, zpool=RAIDZ path= offset= size= error=
Sep 21 05:51:33 freenas manage.py: [middleware.zfs:478] It should be a valid device: gptid/cbad4bef-f9c6-11e1-beef-002215766855
Sep 21 05:51:33 freenas manage.py: [middleware.zfs:478] It should be a valid device: gptid/cc25493d-f9c6-11e1-beef-002215766855
Sep 21 05:51:45 freenas manage.py: [middleware.zfs:478] It should be a valid device: gptid/cbad4bef-f9c6-11e1-beef-002215766855
Sep 21 05:51:45 freenas manage.py: [middleware.zfs:478] It should be a valid device: gptid/cc25493d-f9c6-11e1-beef-002215766855
This is a snapshot of my Volume Status
Any help on how to identify the disks would be great.