VXVM on Solaris ( Sparc ) – Understanding boot Failures
Possible reasons for a boot failure:
- The boot device cannot be opened.
- The system cannot be be booted from unusable or stale plexes.
- A UNIX partition is invalid.
- There are incorrect entries in /etc/vfstab.
- Configuration files are missing or damaged
i) Boot device Cannot be opened
SCSI device 0,0 is not responding
Can’t open boot device
The following are Common Causes for the system PROM being unable to read the boot program from the boot drive:
ii) Cannot boot from unusable or stale Plexes
- If the system was booted from one of the disks made bootable by VXVM with the original boot disk turned off. The systems boots normally, but the plexes that reside on the unpowered disks are stale. If the sytem reboots from the original boot disk with the disk turned back on, the system boots using that stale plex.
- if errors in the VxVM headers on the boot disk prevent VxVM from properly identifying the disk. In this case, VxVM does not know the name of that disk. This is a problem because Plexes are associated with disk names, so any Plexes on the unidentified disk are unusable.
- If the root disk has a failure that affects the root volume Plex. At the next boot attempt, the system still expects to use the failed root Plex for booting. If the root disk mirrored at the time of the failure, an alternate root disk can be specified for booting.
In any of the above situation, vxconfigd display a message describing the error and the recovery advice, then halts the system.
VxVM vxconfigd ERROR V-5-1-1049: System boot disk does not have a valid root plex
Please boot from one of the following disks:
Disk: disk01 Device: c0t1d0s2
vxvm:vxconfigd: Error: System startup failed
The system is down.
Above error informs to boot from alternate disk disk01. Once you boot from the alternate disk, if the Plexes on the original boot disk were simply stale, they are caught up automatically as the system comes up. If, on the other hand, there was a problem with the private area on the disk or the disk failed, you need to re-add or replace the disk.
we can identify the problem, if the failure In the private area of root disk … by running
# vxdisk list
DEVICE TYPE DISK GROUP STATUS
– – rootdisk bootdg failed was: c0t3d0s2
c0t1d0s2 sliced disk01 bootdg ONLINE
iii) Invalid Unix Partition
Error appears like “File just loaded does not appear to be executable “
If this message appears during the boot attempt, the system should be booted from an alternate boot disk. While booting, most disk drivers display errors on the console about the invalid UNIX partition information on the failing disk. The messages are similar to this:
WARNING: unable to read label
WARNING: corrupt label_sdo
iv) Incorrect entries in /etc/vfstab
- Damaged root (/) entry in /etc/vfstab
If the entry in /etc/vfstab for the root (/) file system is lost or is incorrect, the system boots in single-user mode. Messages similar to the following are displayed on booting the system:
INIT: Cannot create /var/adm/utmp or /var/adm/utmpx
INIT: failed write of utmpx entry:” “
# fsck –F ufs /dev/rdsk/c0t0d0s0
# mount –o remount /dev/vx/dsk/rootvol /
After mounting the / as RW just exit the shell, and then the system prompts for the run level. Enter into Run level 3 and restore the /etc/vfstab for / after the system boots.
- Damaged /usr entry in /etc/vfstab
The /etc/vfstab file has an entry for /usr only if /usr is located on separate disk partition. After encapsulation of the disk containing the /usr partition, VxVM changes the entry in /etc/vfstab to use the corresponding volume.
# ok boot cdrom –s à Boot to Single user mode using CDROM
# mount /dev/dsk/c0t0d0s0 /a à mount root (/) file system on /a or /mnt
Edit the /a/etc/vfstab to fix the /usr entry
/dev/vx/dsk/usr /dev/vx/rdsk/usr /usr ufs 1 yes –
Shutdown and reboot the machine from the same root partition on which /usr was restored
v) Missing or damaged configuration files
If /etc/system is damaged or missing, and a saved copy of this file is not available on the root disk, the system cannot be booted with the VxVM rootability feature turned on.
Below steps allow you to boot the system without VxVM rootability and restore configuration file
a. ok> boot cdrom –s
b. # mount /dev/dsk/c0t0d0s0 /a
If backup copy of /etc/system avialble, then restore this as a file /a/etc/system. If no backup then create new /a/etc/system file with the following entries that are require by VxVM:
forceload: drv/ < driver >
To find the driver name in the entry “forceload: drv/ < driver >” just run
# ls –al /dev/dsk/c0t0d0s2
lrwxrwxrwx … /dev/dsk/c0t0d0s2 -> ../../devices/pci@1f,0/pci@1/pci@1/SUNW,isptwo@4/sd@0,0:c
above output indicates that the root disk required “pci” and “sd” drivers. And the entries in /etc/system should look like
Shutdown and reboot the machine with same root partition where the configuration files restored.