# gmirror degraded and disappeared disk



## fluca1978 (Apr 3, 2012)

Hi all,

*S*ince a few days I have a server (7.2-RELEASE) that has a degraded gmirror:


```
# gmirror status
      Name    Status  Components
mirror/gm0  DEGRADED  ad7
```

The other disk in the mirror should be ad5, but there is no such disk on the system:


```
# ls /dev/ad*
/dev/ad7        /dev/ad7s1      /dev/ad7s1a     /dev/ad7s1b     /dev/ad7s1c
```

Since the server is a remote one, I still did not have time to check the hardware by hand, but I suspect the drive is dead. In the logs I've only entries like the followings:


```
# grep -i mirror /var/log/dmesg.boot
Root mount waiting for: GMIRROR
Root mount waiting for: GMIRROR
Root mount waiting for: GMIRROR
Root mount waiting for: GMIRROR
GEOM_MIRROR: Force device gm0 start due to timeout.
GEOM_MIRROR: Device mirror/gm0 launched (1/2).
Trying to mount root from ufs:/dev/mirror/gm0s1a
```

Of course I've tried rebooting the machine, but the situation did not changed at all. Any idea or suggestion? Moreover, is there a way from a degraded mirror to see which are missing components?


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## wblock@ (Apr 3, 2012)

If the other drive isn't even showing up in /dev, sounds like a hardware failure and the mirror is working as expected.

`% diskinfo -v /dev/ad7`
will show the serial number of the working drive, then you can open the machine to look at the drive that doesn't have that serial number.  Check power and signal cables to that drive, also check that it hasn't been disabled in the BIOS.


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