OpenVMS boot failure after turning on Shadowing

[HarrinG]

Modified MODPARAMS.DAT files ofr OpenVMS 7.3-2 to allow for Volume and System Disk shadowing. Ran Auotgen and rebooted system. However, during boot phase the boot BUGCHECKED with the error that it could not convert the system disk to a shadow. System will not boot. Is there a flag to allow me ot boot or a way to turn off System disk shadowing from the P0>>> prompt?

[Volker Halle]

HarrinG,

note that OpenVMS shadowing of the system disk REQUIRES a non-zero allocation class.

What was the bugcheck name ?
What's the status value in R0 ?

To turn off system disk shadowing during boot:

>>> b -fl 0,1 ! assuming SYS0 as system root
SYSBOOT> SET SHADOW_SYS_DISK 0
SYSBOOT> C

Volker.

[HarrinG]

Thanks for the quick response and I used the boot flags 0,1 to set shadow_sys_disk=0 which allowed me to boot.

However, How do I now shadow the system disk? Do I need to create a single member shadow set for the system disk, turn on shadow_sys_disk and reboot or is there something I am missing?

[Volker Halle]

HarrinG,

make sure the SYSGEN parameter ALLOCLASS is set to a non-zero value. Then boot with SHADOW_SYS_DISK = 1 - the system will form a system disk shadowset with the single boot device as a member.

Then add the 2nd member with: MOUNT/SYS DSAx:/SHAD=$n$DKAx: label/CONFIRM and let the shadow-copy add the second member. In the future, the system will search for both members at boot and and add them into the system disk shadowset, if available.

Please look at the system crashdump for the failure to boot with a shadowed system disk:

$ ANAL/CRASH SYS$SYSTEM:
SDA> CLUE CRASH
...
SDA> EXIT

Please report the bugcheck name and the value of R0.

Volker.

[Peter Zeiszler]

Check your SHADOW_SYS_UNIT value. Make sure you don't have another shadow disk with that same unit.

[Ian Miller.]

what is the value of the SHADOWING system parameter?

is this system clustered?

[HarrinG]

Had not properly set ALLOCLASS parameter. Shows how much of a newby I am :)

Thanks to everyone for their assistance.