[Simh] SIMH VAXcluster - shadow disk issues

[Lennert Van Alboom]

Hello there. 


I'm running into issues with disk shadowing in VMS between two SIMH instances.
My setup is as follows:

- 2 SIMH VAX instances running VMS 7.3, fully licensed using hobbyist licenses:
   WHISKY and COGNAC
- Networking was setup using the "taptap" method as described in
   http://www.retrocomputinggeek.com/retrowiki/SIMHNetworking
- Both SIMH network tunX devices are on the same bridge (br0) on the same linux
   host
- DECnet and TCPIP configured and confirmed to be working on both machines:
   WHISKY (1.1, x.y.z.240), COGNAC (1.2, x.y.z.241)
- VAXcluster enabled between both instances: WHISKY has VOTES=1, COGNAC
   VOTES=0, cluster EXPECTED_VOTES=1 with no quorum disk
- ALLOCLASS for WHISKY is set to 240, COGNAC to 241

The Linux host itself is a Xen virtual machine; this is the main reason why I
didn't go for a "dedicated" network interface per simh instance, as this
doesn't play nice with the bridges on the Xen VM host.

At this point, I wanted to play with disk shadowing. Each of the SIMH VAXen has
two disks; one for system (DUA0:), one 'spare' (DUA1:). Both are of type RA90
(1GB). The idea was to shadow those two 'spare' disks.

Commands issued:

$ INIT/ERASE $240$DUA1: CLUSTERDATA
$ INIT/ERASE $241$DUA1: CLUSTERDATA
$ MOUNT/SYSTEM/CLUSTER DSA0: /SHADOW=($240$DUA1:,$241$DUA1:) CLUSTERDATA CLUSTERDATA

At this point, the shadow disk is being created and mounted on both nodes. No
issues there. But the disk copy never actually kicks off:

$ SHOW DEV CLUSTERDATA

Device                  Device           Error    Volume         Free  Trans Mnt
  Name                   Status           Count     Label        Blocks Count Cnt
  DSA0:                   Mounted              0  CLUSTERDATA    2375847     1   2
  $240$DUA1:    (WHISKY)  ShadowSetMember      0  (member of DSA0:)
  $241$DUA1:    (COGNAC)  ShadowCopying        0  (copy trgt DSA0:   0% copied)


Even after 12 hours, it's still at 0%; I think it's safe to say it's not going
to go up. Has anyone ever attempted to do disk shadowing between two SIMH
instances, and if yes, do you have any idea what might be causing this problem?


Thanks,


Lennert