Drive lost, missing or mixed up?

[kingcharles]

Hi,
I have a strange situation on my installation.
It seems as if drives are mixed up or one has been lost.
My config is running the latest release "FreeNAS-8.3.1-RELEASE-p2-x64 (r12686+b770da6_dirty"and was working fine for months until after a reboot initiated by myself via the console (I thought the web GUI was not responding but it turned out I used the wrong IP).
After the reboot one of my mirrors reported an error:

pool: ZRAID_3TB
state: DEGRADED
status: One or more devices could not be opened. Sufficient replicas exist for
the pool to continue functioning in a degraded state.
action: Attach the missing device and online it using 'zpool online'.
see: http://www.sun.com/msg/ZFS-8000-2Q
scan: scrub repaired 0 in 2h41m with 0 errors on Sun Jun 2 02:41:40 2013
config:

NAME STATE READ WRITE CKSUM
ZRAID_3TB DEGRADED 0 0 0
mirror-0 DEGRADED 0 0 0
3970182435941800839 UNAVAIL 0 0 0
was /dev/gptid/c6aa8b3c-3cab-11e2-81d8-3085a93b6cf5
gptid/c7f6af47-3cab-11e2-81d8-3085a93b6cf5 ONLINE 0 0 0

errors: No known data errors

a previous dsmeg says:

ada0 at ahcich0 bus 0 scbus0 target 0 lun 0
ada0: <WDC WD30EZRX-00MMMB0 80.00A80> ATA-8 SATA 3.x device
ada0: 600.000MB/s transfers (SATA 3.x, UDMA6, PIO 8192bytes)
ada0: Command Queueing enabled
ada0: 2861588MB (5860533168 512 byte sectors: 16H 63S/T 16383C)
ada1 at ahcich1 bus 0 scbus1 target 0 lun 0
ada1: <WDC WD30EZRX-00MMMB0 80.00A80> ATA-8 SATA 3.x device
ada1: 600.000MB/s transfers (SATA 3.x, UDMA6, PIO 8192bytes)
ada1: Command Queueing enabled
ada1: 2861588MB (5860533168 512 byte sectors: 16H 63S/T 16383C)
ada2 at ahcich2 bus 0 scbus2 target 0 lun 0
ada2: <ST3500320AS SD1A> ATA-8 SATA 1.x device
ada2: 150.000MB/s transfers (SATA 1.x, UDMA6, PIO 8192bytes)
ada2: Command Queueing enabled
ada2: 476940MB (976773168 512 byte sectors: 16H 63S/T 16383C)
ada3 at ahcich3 bus 0 scbus3 target 0 lun 0
ada3: <ST3500320AS SD1A> ATA-8 SATA 1.x device
ada3: 150.000MB/s transfers (SATA 1.x, UDMA6, PIO 8192bytes)
ada3: Command Queueing enabled
ada3: 476940MB (976773168 512 byte sectors: 16H 63S/T 16383C)
ada4 at ata0 bus 0 scbus4 target 0 lun 0
ada4: <Hitachi HDS721616PLA380 P22OABEA> ATA-7 SATA 2.x device
ada4: 150.000MB/s transfers (SATA, UDMA6, PIO 8192bytes)
ada4: 152627MB (312581808 512 byte sectors: 16H 63S/T 16383C)
da0 at umass-sim0 bus 0 scbus6 target 0 lun 0
da0: <USB Flash Disk 1100> Removable Direct Access SCSI-4 device
da0: 40.000MB/s transfers
da0: 3824MB (7831552 512 byte sectors: 255H 63S/T 487C)

So it seems that all disks are detected at boot that time.

Now the really odd thing is that the web GUI has the disks mixed up and one disk is missing.
ADA1 is showing the wrong serial because it is from one of the 500G drives! But it still lists it as a 3TB drive...
See screenshot of the GUI:

So a look at the latest messages shows:

Jun 15 18:34:00 freenas kernel: ada0 at ahcich0 bus 0 scbus0 target 0 lun 0
Jun 15 18:34:00 freenas kernel: ada0: <WDC WD30EZRX-00MMMB0 80.00A80> ATA-8 SATA 3.x device
Jun 15 18:34:00 freenas kernel: ada0: 600.000MB/s transfers (SATA 3.x, UDMA6, PIO 8192bytes)
Jun 15 18:34:00 freenas kernel: ada0: Command Queueing enabled
Jun 15 18:34:00 freenas kernel: ada0: 2861588MB (5860533168 512 byte sectors: 16H 63S/T 16383C)
Jun 15 18:34:00 freenas kernel: ada1 at ahcich2 bus 0 scbus2 target 0 lun 0
Jun 15 18:34:00 freenas kernel: ada1: <ST3500320AS SD1A> ATA-8 SATA 1.x device
Jun 15 18:34:00 freenas kernel: ada1: 150.000MB/s transfers (SATA 1.x, UDMA6, PIO 8192bytes)
Jun 15 18:34:00 freenas kernel: ada1: Command Queueing enabled
Jun 15 18:34:00 freenas kernel: ada1: 476940MB (976773168 512 byte sectors: 16H 63S/T 16383C)
Jun 15 18:34:00 freenas kernel: ada2 at ahcich3 bus 0 scbus3 target 0 lun 0
Jun 15 18:34:00 freenas kernel: ada2: <ST3500320AS SD1A> ATA-8 SATA 1.x device
Jun 15 18:34:00 freenas kernel: ada2: 150.000MB/s transfers (SATA 1.x, UDMA6, PIO 8192bytes)
Jun 15 18:34:00 freenas kernel: ada2: Command Queueing enabled
Jun 15 18:34:00 freenas kernel: ada2: 476940MB (976773168 512 byte sectors: 16H 63S/T 16383C)
Jun 15 18:34:00 freenas kernel: ada3 at ata0 bus 0 scbus4 target 0 lun 0
Jun 15 18:34:00 freenas kernel: ada3: <Hitachi HDS721616PLA380 P22OABEA> ATA-7 SATA 2.x device
Jun 15 18:34:00 freenas kernel: ada3: 150.000MB/s transfers (SATA, UDMA6, PIO 8192bytes)
Jun 15 18:34:00 freenas kernel: ada3: 152627MB (312581808 512 byte sectors: 16H 63S/T 16383C)
Jun 15 18:34:00 freenas kernel: da0 at umass-sim0 bus 0 scbus6 target 0 lun 0
Jun 15 18:34:00 freenas kernel: da0: <USB Flash Disk 1100> Removable Direct Access SCSI-4 device
Jun 15 18:34:00 freenas kernel: da0: 40.000MB/s transfers
Jun 15 18:34:00 freenas kernel: da0: 3824MB (7831552 512 byte sectors: 255H 63S/T 487C)

One drive disappeared.

As I would like to solve this the proper way and have no idea how to start I am looking for some hints and tips where to start looking. Attached the log files I cut and pasted from.
Thanks.