[Info-vax] Wide area cluster, metro area network, seeking info

[Michael Moroney]

On 6/15/2021 9:24 AM, Arne Vajhøj wrote:
> On 6/11/2021 2:20 PM, Rich Jordan wrote:
>> On Thursday, June 10, 2021 at 10:22:58 AM UTC-5, Marc Van Dyck wrote:
>>> Rich Jordan was thinking very hard :
>>>> We are looking at the possibility of putting VMS boxes in two 
>>>> locations, with
>>>> Integrity boxes running VSI VMS. This is the very beginning of the 
>>>> research
>>>> on the possibility of clustering those two servers instead of just 
>>>> having
>>>> them networked. Probably have to be master/slave since only two 
>>>> nodes and no
>>>> shared storage.
>>>>
>>>> After reviewing the various cluster docs, they seem to be focused on 
>>>> older
>>>> technologies like SoNET and DS3 using FDDI bridges (which would 
>>>> allow shared
>>>> storage). The prospect has a metropolitan area network but I do not 
>>>> have any
>>>> specs on that as yet.
>>>>
>>>> Are there available docs relevant to running a distributed VMS 
>>>> cluster over a
>>>> metro area network or fast/big enough VPN tunnel? Or is that just the
>>>> straight cluster over IP configuration in the docs (which we've 
>>>> never used)
>>>> that we need to concentrate on?
> 
>>> Before going into the technical details, wouldn't it be interersting to
>>> know what you want to achieve, and discuss whether clustering is the
>>> best way to achieve it ? I, for one, would be interested to know why
>>> you
>>> believe that clustering without shared storage can be more beneficial
>>> than simple networking.
> 
>> The point: the system at the second location will be a backup site
>> and/or disaster recovery box.  There is no third location and I have
>> no info on the likelihood of getting one.
> If the business problem is to ensure that the second location always
> have a copy of all data, then a VMS cluster may not be the optimal
> solution.
> 
> There are other VMS features/products than clustering that could
> be relevant.

It appears to me one possibility is fiberchannel presenting RAID-1 
units, with one member of each RAID-1 at the main site and one at the 
backup site connected with dark fiber (FOIP?). VMS system (no cluster) 
at main site and either no system or a cold backup at the backup site.