[Simh] [Bulk] SIMH VAXcluster - shadow disk issues

[Graham Burley]

Any shadow server messages in the operator log?

What's SHADOW_MAX_COPY set to?



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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