OK, so this has now bitten me twice on a new install.

Basically, put Solaris 10u5 on certain machines, and it will work fine until you edit the /etc/vfstab and forget to add a terminating newline to one of your entries.

Upon reboot you will get something like this:

Error: svc:/system/filesystem/root:default failed to mount /boot (see 'svcs -x' for details)
[ system/filesystem/root:default failed fatally (see 'svcs -x' for details) ]
Requesting System Maintenance Mode
Console login service(s) cannot run

At the top of the output from svcs, you’ll see:

svc:/system/filesystem/root:default (root file system mount)
Reason: Start method exited with $SMF_EXIT_ERR_FATAL
see: http://sun.com/msg/SMF-8000-KS
see: /etc/svc/volatile/system-filesystem-root:default.log
Impact: 44 dependent services are not running. (use -v for list.)

The problem is that missing newline, which means the mount table is never parsed correctly.

To fix, enter your root password to get into admin mode. You’ll need to first remount the root fs as read/write:

# mount -orw,remount

And then add that offending missing line end:

# echo >>/etc/vfstab

Be careful with that second line; miss a > symbol and you’ll wipe out your vfstab altogether.

Now reboot, and things should be back to normal.