topic Re: How to undo $ SET SHADOW /SITE=1 in Operating System - OpenVMS

How to undo $ SET SHADOW /SITE=1

David Rabahy 1 — Mon, 23 Nov 2009 21:00:17 GMT

How does one undo $ SET SHADOW /SITE=1?

$ show shadow dsa101
_DSA101: Volume Label: MSOFT01
Virtual Unit State: Steady State
Enhanced Shadowing Features in use:
Dissimilar Device Shadowing (DDS)

VU Timeout Value 3600 VU Site Value 0
Copy/Merge Priority 5000 Mini Merge Disabled
Recovery Delay Per Served Member 30
Merge Delay Factor 200 Delay Threshold 200

Device $1$DKC101 Master Member
Read Cost 2 Site 0
Member Timeout 120

Device $1$DGA11803
Read Cost 501 Site 0
Member Timeout 120

Device $1$DGA12803
Read Cost 501 Site 0
Member Timeout 120
$ set shadow/site=1 DSA101
$ show shadow dsa101
_DSA101: Volume Label: MSOFT01
Virtual Unit State: Steady State
Enhanced Shadowing Features in use:
Dissimilar Device Shadowing (DDS)

VU Timeout Value 3600 VU Site Value 1
Copy/Merge Priority 5000 Mini Merge Disabled
Recovery Delay Per Served Member 30
Merge Delay Factor 200 Delay Threshold 200

Device $1$DKC101 Master Member
Read Cost 42 Site 0
Member Timeout 120

Device $1$DGA11803
Read Cost 501 Site 0
Member Timeout 120

Device $1$DGA12803
Read Cost 501 Site 0
Member Timeout 120
$ set shadow /site=0 dsa101
%SYSTEM-F-BADPARAM, bad parameter value

Re: How to undo $ SET SHADOW /SITE=1

Robert Brooks_1 — Mon, 23 Nov 2009 21:08:13 GMT

Well, the help *does* say that the valid values are 1 to 254 (which isn't correct, because it does accept -1, which displays as the expected large positive integer).

I suspect the quickest way is to remove it from the shadow set. Use of mini-copy might make adding it back into the shadow set somewhat less painful than otherwise.

Please formally notify HP.

I'll see what I can do internally to get this dealt with.

-- Rob

Re: How to undo $ SET SHADOW /SITE=1

Hoff — Mon, 23 Nov 2009 21:43:38 GMT

FWIW... The following are accepted through the parser...

$ set shadow /nosite
$ set shadow /nosite=0

but are equally ineffective at clearing the site setting.

Re: How to undo $ SET SHADOW /SITE=1

David Rabahy — Mon, 23 Nov 2009 21:53:17 GMT

Hi Rob,

Bizarre; what made you think to try -1? Although -1 and other negative numbers through -(2^32-1) are accepted it is undocumented -- I for one wouldn't call that valid per se.

I don't understand your suggestion. I think you're saying to remove a member from the shadow set. The site value is set on the shadow set itself; not on a member.

Hi Hoff,

Nice tries.

Here's a roundabout way to get where I want;

$ set shadow/site=-2147483648 dsa101
$ show shadow dsa101
_DSA101: Volume Label: MSOFT01
Virtual Unit State: Steady State
Enhanced Shadowing Features in use:
Dissimilar Device Shadowing (DDS)

VU Timeout Value 3600 VU Site Value 0
Copy/Merge Priority 5000 Mini Merge Disabled
Recovery Delay Per Served Member 30
Merge Delay Factor 200 Delay Threshold 200

Device $1$DKC101 Master Member
Read Cost 42 Site 0
Member Timeout 120

Device $1$DGA11803
Read Cost 65535 Site 0
Member Timeout 120

Device $1$DGA12803
Read Cost 501 Site 0
Member Timeout 120

Thanks,
David.

Re: How to undo $ SET SHADOW /SITE=1

Robert Brooks_1 — Tue, 24 Nov 2009 19:57:03 GMT

I don't understand your suggestion. I think you're saying to remove a member from the shadow set. The site value is set on the shadow set itself; not on a member.

--

Well, the /SITE qualifier is valid for both a virtual unit and a member unit. I haven't looked at the code lately, but I suspect that
specifying the virtual unit is a "shorthand" way of applying the same value to all members devices. Given that, removing and re-adding a member would effectively clear the site specification.

In fact, check out the help for $ SET DEVICE /SITE (note, that's DEVICE, not SHADOW). For some reason, the help is slightly different for the two variants, even though they do the exact same thing.

-- Rob

Re: How to undo $ SET SHADOW /SITE=1

Malcolm Wade — Wed, 25 Nov 2009 22:41:02 GMT

Well, the /SITE qualifier is valid for both a virtual unit and a member unit. I haven't looked at the code lately, but I suspect that
specifying the virtual unit is a "shorthand" way of applying the same value to all members devices. Given that, removing and re-adding a member would effectively clear the site specification.

------

Note quite so; in a multisite cluster with disks in multiple sites each device is assigned its site code; for each server, the DSA device has its site code assigned. This code will be different on each server in a cluster based on where the server is located.

It's done this way so the VMS server has knowledge of which site it is in and can therefore read off its local shadowset member.

Malcolm

PS. G'day Dave; long time no hear!