maximum number RDF devices per RDF group

[dynamox]

A unique RDF group if you need to replicate between different target arrays, or if you have multiple RDF adapters and you want to have some devices use one set of RDF adapters and another set of devices use another set of RDF adapters.

[LearnEverything]

So if I have different arrays then I will use different RDF groups for organization. However, what about just 2 machines (storage arrays) with SRDF/S, why would I create more than one group per array?

What do you mean by RDF adapters? Why wouldn't I just share all the adapters among one group?

[dynamox]

LearnEverything wrote:

So if I have different arrays then I will use different RDF groups for organization. However, what about just 2 machines (storage arrays) with SRDF/S, why would I create more than one group per array?

you typically wouldn't for SRDF/S where you can manipulate RDF relationships separately (versus SRDF/A). For example look at the below configuration. I am using 4 RF adapters between array 1234 and 9999, same RA rdfg group 9. We started out with 2 adapters but then upgraded to 4 to give us better write response times on SRDF/S devices.

symcfg -sid 1234 list -ra ALL -switched


Symmetrix ID: 000000001234 (Local)


            S Y M M E T R I X    R D F    D I R E C T O R S




         Local            Group      Link              Remote            
--------------------- -------------- ---- -------------------------------
        Po                                                    Po         
         r                      FLGS FLGS                      r         
Ident    t  RA Grp  T Name       SH   SH  SymmID       Ident   t  RA Grp 
------  -- -------- - -------------- ---- ------------ ------ -- --------


RF-1E    4        - -     -      --   --  -            -       -        -
         5        - -     -      --   --  -            -       -        -
         6        - -     -      --   --  -            -       -        -
         7   3 (02) D 1234to5678 ..   X.  000197805678 RF-3E   7   3 (02)
         7  10 (09) D 1234to9999 ..   X.  000196709999 RF-1F   7  10 (09)


RF-2E    4        - -     -      --   --  -            -       -        -
         5        - -     -      --   --  -            -       -        -
         6        - -     -      --   --  -            -       -        -
         7  10 (09) D 1234to9999 ..   X.  000196709999 RF-2F   7  10 (09)


RF-3E    4        - -     -      --   --  -            -       -        -
         5        - -     -      --   --  -            -       -        -
         6        - -     -      --   --  -            -       -        -
         7  10 (09) D 1234to9999 ..   X.  000196709999 RF-3F   7  10 (09)


RF-4E    4        - -     -      --   --  -            -       -        -
         5        - -     -      --   --  -            -       -        -
         6        - -     -      --   --  -            -       -        -
         7   3 (02) D 1234to5678 ..   X.  000197805678 RF-2E   7   3 (02)
         7  10 (09) D 1234to9999 ..   X.  000196709999 RF-4F   7  10 (09)

[LearnEverything]

I see, but they are all under the same RDF group (09).

[dynamox]

they are in my case but could be in different groups. For example let's say you want to "pin" some devices to use a particular set of RDF adapters because you want to use it for  your ultra response time sensitive devices (Oracle REDO logs for example).  So for those devices you could specify a different group even though it's connecting to the same array.

[LearnEverything]

Different RA's have different characteristics? Aren't they all the same adapters connected to the front end of the same type of directors?

How do I assign TDEVs to specific RDF groups?

[dynamox]

same characteristics but could have different load based on how many devices are using them. You specify RDF group when you create RDF pair.

[LearnEverything]

We use all TDEVs as RDFs as well, but when I provision a LUN I just assign it as Dynamic RDF without other SRDF configurations.

Where in this process do I specify the RDF group?

[dynamox]

when you create RDF relationship

symrdf -sid 1234 -f myfilewithsource_target_devices.txt  -type R1 -invalidate R2 -rdfg 11

[LearnEverything]

What does the "txt" file consist of as in what format and how does it look like?