A colleague of mine came across this message during a bosboot on one of our AIX 6.1 LPARs:

                                                                        

# bosboot -a -d /dev/hdisk0                                           

Error opening disk: There is an input or output error.                 

Error opening disk: There is an input or output error.                 

Error opening disk: There is an input or output error.                 

Error opening disk: There is an input or output error.                 

                                                                       

bosboot: Boot image is 40978 512 byte blocks.                           

                                                                       

# oslevel -s                                                           

6100-03-01-0921                                                        

                                                                        

I’d not seen this message before. I checked the system for any obvious errors in the AIX error report (errpt). I also checked that hdisk0 was identified as a bootable disk (ipl_varyon –i). No issues were found.

                                                                     

We found some hits for this message in the IBM support database.

                                                                       

“The bosboot script calls bootinfo and this binary has code in place which tries to identify the disk that the system was last booted off. In this case it is getting an error when trying to open some disk, not necessarily hdisk0. The boot image seems to have been successfully written to hdisk0.                                                      

                                                                       

To check what disk it is complaining about can you grab truss as follows:                                                               

                                                                        

# truss -eaf -o /tmp/bosboot.truss bosboot -ad /dev/hdisk0               

                                                                       

and then:           

                                                   

# grep EIO /tmp/bosboot.truss”                                          

                                                                       

The bootinfo command was reporting the same message on this system.            

                                                                       

# bootinfo -v                                                         

Error opening disk: There is an input or output error.                 

hd5                                                                     

 

I ran truss against the bosboot command and found that hdisk9 was the culprit.

                                                                       

802916: kopenx("/dev/hdisk9", O_RDONLY, , 8)    Err#5  EIO      

                                                                       

It appeared that bootinfo was trying to reference hdisk9, which did not belong to a volume group?                                                            

                                                                        

# lspv                                                                 

hdisk0      00c01c70a73dd4e4  rootvg      active                                  

hdisk9      00c01c70089b6ed3  None               

                                                                      

The system originally booted from hdisk9. Then the boot list was changed back to hdisk0. The system was migrated to AIX 6.1 on hdisk9. hdisk0 contained the previous version of AIX 5.3. After the migration, hdisk0 was added to rootvg and mirrored with hdisk9. Then hdisk9 was unmirrored and removed from rootvg.                                                                                     

                                                                        

# bootinfo -b                                                          

hdisk9                                                                 

                                                                       

# bootlist -m normal -o                                                

hdisk0 blv=hd5                                                         

hdisk0 blv=hd5               

                                                                                                                     

We later discovered that hdisk9 was removed from the VIO server and not from the client. Whoops! This resulted in the I/O error during the bosboot. Upon removing the disk from the client, the bosboot command returned the following message:                                                     

                                                                       

# bosboot -a -d /dev/hdisk0                                            

unable to identify boot disk                                            

unable to identify boot disk                                           

unable to identify boot disk                                           

unable to identify boot disk                                           

                                                                        

bosboot: Boot image is 40978 512 byte blocks.                          

                                                                       

We had come across this message a few times already. It appeared to be related to the mirroring/unmirroring of disks in rootvg. However, based on our experience this message was OK to ignore. After a reboot this message will no longer appear. Others have also reported this problem.

                                                                       

This is not the first time that bosboot has displayed this message, refer to the following APAR:

   

APAR: IY96817: BOSBOOT DISPLAYS "UNABLE TO IDENTIFY BOOT DISK"

 

We’ve asked IBM support if there are any recent APARs for AIX 6.1 that might relate to this message. I’ll let you know if we find an answer.