Broken mirror - help understanding this...

[Norberto Meijome]

Hi there,
I have a 2 RAID 1 mirrors brake in front of my eyes, pretty much. they 
were based on ad4 and ad8 (SATA drives, the board has 2 SATA 
controllers). It seems ad4 either died or the primary controller did. I 
was writing several GBs of data to the 'mirror_data' device and...poof :-/

Can anyone tell from the info below whether it's the disk that died, or 
that controller? anyone seen anything like this before? (sorry, new to 
gmirror). Any tests that can be suggested (other than surface test, 
which I'll have to do after the weekend).

6.0-BETA3 (dual) amd64, SMP kernel, on a Tyan GT24b2891  
http://tyan.com/products/html/gt24b2891_spec.html ).

ad4: 238475MB <WDC WD2500JS-00MHB0 02.01C03> at ata2-master SATA150

# gmirror status
              Name    Status  Components
      mirror/gm0s1  DEGRADED  ad8s1
mirror/mirror_data  DEGRADED  ad8s2

/var/log/messages :
-----
Sep  3 00:43:29 cerberus kernel: subdisk4: detached
Sep  3 00:43:29 cerberus kernel: ad4: detached
Sep  3 00:43:29 cerberus kernel: unknown: TIMEOUT - WRITE_DMA48 retrying 
(1 retrGy ElOeMf_tMI)RROR :L BDAe=vic3e7 5m8i1r3r4o0r1_d
Sep  3 00:43:29 cerberus kernel: ata: provider ad4s2 disconnected.
Sep  3 00:43:29 cerberus kernel: GEOM_MIRROR: Request failed (error=6). 
ad4s2[WRITE(offset=65536, length=2048)]
Sep  3 00:43:29 cerberus kernel: GEOM_MIRROR: Request failed (error=6). 
ad4s2[WRITE(offset=6144000, length=16384)]
Sep  3 00:43:29 cerberus kernel: GEOM_MIRROR: Request failed (error=6). 
ad4s2[WRITE(offset=6160384, length=4096)]
Sep  3 00:43:29 cerberus kernel: GEOM_MIRROR: Request failed (error=6). 
ad4s2[WRITE(offset=64920735744, length=2048)]
Sep  3 00:43:29 cerberus kernel: GEOM_MIRROR: Request failed (error=6). 
ad4s2[WRITE(offset=178580144128, length=16384)]
Sep  3 00:43:29 cerberus kernel: GEOM_MIRROR: Request failed (error=6). 
ad4s2[WRITE(offset=179928645632, length=16384)]
Sep  3 00:43:29 cerberus kernel: GEOM_MIRROR: Request failed (error=6). 
ad4s2[WRITE(offset=180121288704, length=16384)]
Sep  3 00:43:29 cerberus kernel: GEOM_MIRROR: Request failed (error=6). 
ad4s2[WRITE(offset=180313931776, length=16384)]
Sep  3 00:43:29 cerberus kernel: GEOM_MIRROR: Request failed (error=6). 
ad4s2[WRITE(offset=180506574848, length=16384)]
Sep  3 00:43:29 cerberus kernel: GEOM_MIRROR: Request failed (error=6). 
ad4s2[WRITE(offset=180699217920, length=16384)]
Sep  3 00:43:29 cerberus kernel: GEOM_MIRROR: Request failed (error=6). 
ad4s2[WRITE(offset=180891860992, length=16384)]
Sep  3 00:43:29 cerberus kernel: GEOM_MIRROR: Request failed (error=6). 
ad4s2[WRITE(offset=181084504064, length=16384)]
Sep  3 00:43:29 cerberus kernel: GEOM_MIRROR: Request failed (error=6). 
ad4s2[WRITE(offset=181277147136, length=16384)]
Sep  3 00:43:29 cerberus kernel: GEOM_MIRROR: Request failed (error=6). 
ad4s2[WRITE(offset=181315141632, length=32768)]
Sep  3 00:43:29 cerberus kernel: GEOM_MIRROR: Request failed (error=6). 
ad4s2[WRITE(offset=181682601984, length=131072)]
Sep  3 00:43:29 cerberus kernel: GEOM_MIRROR: Request failed (error=6). 
ad4s2[WRITE(offset=181682733056, length=131072)]
Sep  3 00:43:29 cerberus kernel: GEOM_MIRROR: Request failed (error=6). 
ad4s2[WRITE(offset=181682864128, length=131072)]
Sep  3 00:43:29 cerberus kernel: GEOM_MIRROR: Request failed (error=6). 
ad4s2[WRITE(offset=181682995200, length=131072)]
Sep  3 00:43:29 cerberus kernel: GEOM_MIRROR: Request failed (error=6). 
ad4s2[WRITE(offset=181683126272, length=131072)]
Sep  3 00:43:29 cerberus kernel: GEOM_MIRROR: Request failed (error=6). 
ad4s2[WRITE(offset=181683257344, length=131072)]
Sep  3 00:43:29 cerberus kernel: GEOM_MIRROR: Request failed (error=6). 
ad4s2[WRITE(offset=181683388416, length=131072)]
Sep  3 00:43:29 cerberus kernel: GEOM_MIRROR: Request failed (error=6). 
ad4s2[WRITE(offset=181683519488, length=131072)]
Sep  3 00:43:29 cerberus kernel: GEOM_MIRROR: Device gm0s1: provider 
ad4s1 disconnected.
Sep  3 00:43:30 cerberus kernel: unknown: timeout waiting to issue command
Sep  3 00:43:30 cerberus kernel: unknown: error issueing WRITE_DMA48 command
Sep  3 00:43:30 cerberus kernel: GEOM_MIRROR: Request failed (error=6). 
ad4s2[WRITE(offset=181682470912, length=131072)]
-----

thanks for any help!!
Beto