Hello, i'm reading the support page: HyperSwap configuration without using interswitch links .

I need some clarifications:

1. When it says "without using interswitch links" is it speaking only about the intracluster communication between nodes or also for the ports for Hosts I/O? 
2. It assumes that there is a "public san" dedicated only for host I/O? 
3. Flashsystems ports for hosts I/O needs cabled only to the 2 local switches? 
4. If a host from site1 writes a volume that is primary on site2 would pass on public san ISL?
5. There is some sort of drawing of this solution?
6. What's the recommended total number of ports per control enclosure with this configuration on FS7300?

thanks

best regards

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Davide Galbussera
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Hi Davide:

pls see responses inline for your questions I got an answer handy:

1. When it says "without using interswitch links" is it speaking only about the intracluster communication between nodes or also for the ports for Hosts I/O? 
   A: this pertains to intra-cluster communication, more precisely: communication between the I/O groups
   
   
2. It assumes that there is a "public san" dedicated only for host I/O? 
   A: not necessarily a requirement, although recommended in order to isolate the different kinds of traffic
   
   
3. Flashsystems ports for hosts I/O needs cabled only to the 2 local switches? 
   A: yes
   
   
4. If a host from site1 writes a volume that is primary on site2 would pass on public san ISL?
   A: in HyperSwap, there is no fixed primary/secondary site. The replication direction rather is determined by the majority of host writes.
   
   
5. There is some sort of drawing of this solution?
   A: IBM Redbook "IBM Storwize V7000, Spectrum Virtualize, HyperSwap, and VMware Implementation", chapter 3.4.1  No ISL configuration contains below illustration: 
   
   
   

------------------------------
Best regards, 

Christian Schroeder
IBM Storage Virtualize Support with Passion
------------------------------

Hi Christian, thanks! now it's crystal clear. 

best regards

------------------------------
Davide Galbussera
------------------------------

Original Message:
Sent: Mon September 04, 2023 08:51 AM
From: Christian Schroeder
Subject: HyperSwap without using ISLs

Hi Davide:

pls see responses inline for your questions I got an answer handy:

1. When it says "without using interswitch links" is it speaking only about the intracluster communication between nodes or also for the ports for Hosts I/O? 
   A: this pertains to intra-cluster communication, more precisely: communication between the I/O groups
   
   
2. It assumes that there is a "public san" dedicated only for host I/O? 
   A: not necessarily a requirement, although recommended in order to isolate the different kinds of traffic
   
   
3. Flashsystems ports for hosts I/O needs cabled only to the 2 local switches? 
   A: yes
   
   
4. If a host from site1 writes a volume that is primary on site2 would pass on public san ISL?
   A: in HyperSwap, there is no fixed primary/secondary site. The replication direction rather is determined by the majority of host writes.
   
   
5. There is some sort of drawing of this solution?
   A: IBM Redbook "IBM Storwize V7000, Spectrum Virtualize, HyperSwap, and VMware Implementation", chapter 3.4.1  No ISL configuration contains below illustration: 
   
   
   

------------------------------
Best regards, 

Christian Schroeder
IBM Storage Virtualize Support with Passion
------------------------------