[Info-vax] VMS QuickSpecs

[Dirk Munk]

Stephen Hoffman wrote:
> On 2015-08-13 20:09:30 +0000, Dirk Munk said:
>
>> FCIP is a protocol to tunnel FC over long distances. IP over FC is in
>> principle the same as IP over ethernet.
>
> Yes, and those are the same links where you'd want to have IPFC.
> Locally, there's rather less of a requirement for FCIP, as 10 GbE and 40
> GbE switches and networks are usually available.

No, IPFC is not at all for long distance interconnects. That would meen 
you would have very long distance firbechannel interconnects. FCIP on 
the other hand is used to tunnel FC over long distance IP connections.

If you already have a fibrechannel infrastructure available, and if your 
systems already have fibrechannel connections, then using IPFC becomes a 
very different matter.

IP over fibrechannel can not be routed. You always use zones in 
fibrechannel. with IPFC a zone becomes a very effective, fast and secure 
VPN.

Suppose you have two (or more) servers communicating very intensively 
with each other. Put them in one zone (or two, since you will have two 
fibrechannel networks) (you can even use virtual HBAs) and you will have 
an extremely fast, secure and efficient IP interconnect at zero costs.

This is the reason that I would like to see network communication over 
fibrechannel for VMS. You can use it for IP, clustering, perhaps even 
DECnet.

>
>> I tried on Solaris, it was extremely fast.   With IPv6 you can have a
>> packetsize of 16MB, not much protocol overhead.
>
> Apollo had gonzo fast networking, and look where they ended up.
>
>> I meant fibrechannel as such, not the VMS implementation. Fibrechannel
>> was supposed to be the successor of FDDI.
>
> Many products are supposed to be the successor to many products.  Those
> plans don't always work out.
>
> Irrespective of FCIP, FC itself does not appear to have a particularly
> robust future, particularly given the encroachment of cheaper and
> usually "good enough" storage hardware below, and given gonzo-grade
> InfiniBand storage above.  (I'd expect scale-out over scale-up too, but
> you're a far firmer believer in the efficacy and applicability of
> ginormous servers than I am.)

Fibrechannel is very robust, big companies like it. 128Gb/sec 
firbechannel is on the roadmap. What you see with ethernet is that 
storage over ethernet uses its own interfaces, it will not use the same 
interfaces as used for other connections. A typical x86 server has many 
ethernet ports, all with a different function.

I absolutely like infiniband, but is still is a bit of a niche product.

In my view, fibrechannel will stay, and will be the dominant storage 
interconnect in big datacenters until there is a very different way to 
connect to (flash) storage.

>
> <http://www.mellanox.com/related-docs/whitepapers/WP_Scalable_Storage_InfiniBand_Final.pdf>
>
>
> Whether the VMS I/O stacks — whether we're discussing the storage or
> networking stacks, or the file system itself — can even go fast enough
> to reasonably deal with this stuff is an open question, too.
>
> But all this is fodder for VSI.
>
>