Recently I installed FreeBSD 10.1 on machine that for years was working fine with FreeBSD 6.2. Since machine is located in datacenter I configured remote access via serial console.

After installation I encountered a weird problem on boot.
Every reboot the rootfs cannot be mounted.

uhub4: 8 ports with 8 removable, self powered
Trying to mount root from ufs:/dev/raid/r0p2 [rw]...
mountroot: waiting for device /dev/raid/r0p2 ...
Mounting from ufs:/dev/raid/r0p2 failed with error 19.

Loader variables:
  vfs.root.mountfrom=ufs:/dev/raid/r0p2
  vfs.root.mountfrom.options=rw

Manual root filesystem specification:
  <fstype>:<device> [options]
  Mount <device> using filesystem <fstype>
  and with the specified (optional) option list.

  eg. ufs:/dev/da0s1a
  zfs:tank
  cd9660:/dev/acd0 ro
  (which is equivalent to: mount -t cd9660 -o ro /dev/acd0 /)

  ?  List valid disk boot devices
  .  Yield 1 second (for background tasks)
  <empty line>  Abort manual input

mountroot>

but when I press enter (via attached keyboard or serial console) I can see the following, the system reboots just fine

mountroot>
panic: mountroot: unable to (re-)mount root.
cpuid = 0
KDB: stack backtrace:
#0 0xffffffff80963000 at kdb_backtrace+0x60
#1 0xffffffff80928125 at panic+0x155
#2 0xffffffff809c554f at vfs_mountroot+0x1eaf
#3 0xffffffff808d7533 at start_init+0x53
#4 0xffffffff808f8b6a at fork_exit+0x9a
#5 0xffffffff80d0acbe at fork_trampoline+0xe
Uptime: 12s
Automatic reboot in 15 seconds - press a key on the console to abort

now system reboots and everything goes fine

Trying to mount root from ufs:/dev/raid/r0p2 [rw]...
Setting hostuuid: 530c9cf5-a7e5-11e4-97b5-00e08146563c.
Setting hostid: 0xe4218f4f.
Entropy harvesting: interrupts ethernet point_to_point swi.
Starting file system checks:
/dev/raid/r0p2: FILE SYSTEM CLEAN; SKIPPING CHECKS
/dev/raid/r0p2: clean, 7232943 free (983 frags, 903995 blocks, 0.0% fragmentation)
/dev/raid/r1s1f: FILE SYSTEM CLEAN; SKIPPING CHECKS
/dev/raid/r1s1f: clean, 41630678 free (104646 frags, 5190754 blocks, 0.1% fragmentation)
/dev/raid/r0p4: FILE SYSTEM CLEAN; SKIPPING CHECKS
/dev/raid/r0p4: clean, 49146170 free (8498 frags, 6142209 blocks, 0.0% fragmentation)
Mounting local file systems:.
Writing entropy file:.

I just thought that if the system auto rebooted when it cannot mount root (which I guess is due to kernel panic), I could have this system working fine, it would just reboot twice.

I found similar thread but related to linux, where I could set /etc/sysctl variable and have system autoreboot on kernel panic

kernel.panic = 20

Automatic Reboot after Kernel Panic

It doesn't seem to work on FreeBSD though.
My question is is there a way I can make this system to autoreboot when rootfs cannot be mounted? I hope it might reboot and mount root just fine on the second run?

I will also appreciate any other suggestions.

Thanks

comment1:

I was requested to output some data from server settings, here is it:

nn@d02:~ % uname -a
    FreeBSD hostname 10.1-RELEASE-p19 FreeBSD 10.1-RELEASE-p19 #0: Sat Aug 22 03:55:09 UTC 2015     root@amd64-builder.daemonology.net:/usr/obj/usr/src/sys/GENERIC  amd64

nn@d02:~ % freebsd-version -k
10.1-RELEASE-p19

nn@d02:~ % freebsd-version -u
10.1-RELEASE-p19

nn@d02:~ % gpart show
=>       34  488390589  raid/r0  GPT  (233G)
         34       1024        1  freebsd-boot  (512K)
       1058   62914560        2  freebsd-ufs  (30G)
   62915618    8388608        3  freebsd-swap  (4.0G)
   71304226  417086396        4  freebsd-ufs  (199G)
  488390622          1           - free -  (512B)

=>       63  488390593  raid/r1  MBR  (233G)
         63  488375937        1  freebsd  [active]  (233G)
  488376000      14656           - free -  (7.2M)

=>        0  488375937  raid/r1s1  BSD  (233G)
          0    1048576          1  freebsd-ufs  (512M)
    1048576    8324192          2  freebsd-swap  (4.0G)
    9372768    6258688          4  freebsd-ufs  (3.0G)
   15631456    1048576          5  freebsd-ufs  (512M)
   16680032  471695905          6  freebsd-ufs  (225G)

nn@d02:~ % graid show
graid: Unknown command: show.

nn@d02:~ % graid status
   Name   Status  Components
raid/r0  OPTIMAL  ada0 (ACTIVE (ACTIVE))
                  ada1 (ACTIVE (ACTIVE))
raid/r1  OPTIMAL  ada2 (ACTIVE (ACTIVE))
                  ada3 (ACTIVE (ACTIVE))