[Simh] SIMH VAXcluster - shadow disk issues

[Nathan Cutler]

Hi Lennert, if you don't get immediately effective help here, you
might try reposting your question on the VMS newsgroup - comp.os.vms -
disk shadowing comes up there frequently.

Nathan

On Fri, Jan 20, 2012 at 8:10 AM, Lennert Van Alboom
<lennert at vanalboom.org> wrote:
> 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
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