System Boot ProblemsTroubleshooting ftServer Systems 9-3N O T EIf a RAID array fails to start, the boot stops and enters adebug shell. This is almost always because of aconfiguration error in /etc/fstab or/etc/mdadm.conf. Exiting the shell forces a reboot.Depending on your system’s RAID configuration, you may see one or more errormessages similar to the following:md: could not bd_claim sdar1md: error, md_import_device() returned -16These messages indicate that md is refusing to start an array that has already beenstarted. You can safely ignore them.The recommended configuration has all RAID-1 arrays marked as type 0xfd (LinuxRAID autodetect) so they start early, and all RAID-0 arrays in /etc/mdadm.conf,so they start later.• The operating system checks the file systems.N O T EIn the case of crash recovery, the file check (fsck) maytake a long time, and it may fail. If it fails, the boot stopsand enters a debug shell. The administrator mustmanually repair the problem file systems. Exiting the shellforces a reboot.Possible Boot ProblemsA problem in booting the system may be associated with missing or corruptfault-tolerant drivers, the GRUB boot loader, or RAID.Missing Drivers Prevent BootingIf required fault-tolerant drivers are not present at boot time, and if the system’sfault-tolerant policy is set to prevent booting when drivers are missing (the defaultsetting), the following prompt appears at the console:This system is not fault tolerant becausereasonType "NON-FT-BOOT" to allow login for repair:
