[Info-vax] Boot drive died on a shadowed system disk

[Jan-Erik Soderholm]

Rich Jordan wrote 2012-05-17 18:36:
> Based on the docs I think we're ok but its the first time this has
> happened so if anyone knows for certain please feel free to comment.
>
> DS10. OpenVMS V8.2, ECOs current.  Two channel KZPEA SCSI controller,
> two drives on each channel; drive DKA0 is the console selected boot
> disk.  System shadow disk DSA0 contains DKA0 and DKB0, the data unit
> DSA1 has drives DKA100 and DKB100.  Console AUTO_ACTION is RESTART.
>
> DKA0 failed out of the shadowset with hard errors (DKB0 failed out of
> DSA1 shortly thereafter, but was able to rejoin manually).  DKA0 will
> not remount into DSA0 (got the following error):
>
> $ MOUNT/SYSTEM  DSA0 /SHADOW=$1$DKA0: ALPHASYS /CONFIRM
> %MOUNT-I-MOUNTED, ALPHASYS mounted on _DSA0:
> %MOUNT-I-SHDWMEMFAIL, _$!$DKA0: (NODE) failed as a member of the
> shadow set.
> -SYSTEM-F-ABORT, abort
> %MOUNT-I-ISAMBR, _$1$DKB0: (NODE) is a member of the shadow set
>
> No errors were logged against the DKA0 device from this mount attempt
> but one bus error on PKA0 was.  We're not certain yet which component
> or components are at fault (a support call is being placed).
>
> I can mount DKA0 locally/writelocked and have run an analyze/disk on
> it (with some cleanup indicated as needed).
>
> I suppose I could mount it /override=shadow then dismount and try to
> have it rejoin the set but I don't think its trustworthy so not going
> to try.
>
> My question is this.  In the event of a reboot before service can be
> performed, what will happen?  My expectation based on the shadow docs
> is one of two, either of which are survivable.
>
> DKA0 is nonbootable:  the system just fails at console level, and can
> either have its console boot device changed to DKB0 or just manually
> booted from DKB0.
>
> DKA0 is at least nominally bootable:  the system starts to boot, sees
> the shadow info (so long as I don't mount it /OVERRIDE=SHADOW!), looks
> to DKB0 and sees the severe mismatch and that DKA0 was not a valid
> member if the set.  It then fails the boot with a SHADBOOTFAIL
> bugcheck and someone onsite still has to manually boot from DKB0.
>
> I don't see a way for the system to actually come up on the outdated
> DKA0: disk.  Just bootfailures if it goes down.  Is this correct?

Can't the DS10 have two devices as default boot device?
The though is to have a system that always boots when one
of the system disks is "gone".

Why do you want to boot a disk that is "dead"?
Boot from DKB0 and replace DKA0.