[Imported] Hot Standby per Main-Standby situation after reconnect

[sbeadle]

>>Message imported from previous forum - Category:ClearSCADA Software<<
User: florian, originally posted: 2018-10-25 19:28:58 Id:280
This is a re-posting from the obsoleted (October 2018) "Schneider Electric Telemetry & SCADA" forum.

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**_FeWo:_**
**_Hello, i have a question according to a hot-standby Setup. I want to have the following behavior:_**

**_Server A is Main, Server B standby._**

**_I Isolate Server A from Network - Server B goes Main._**

**_I reconnect Server A to the Network._**

**_Now i want to Keep the Server B as main.Same behaivior i want to have for the Situation that Server A is standby and Server B is main_**

**_- after disconnect and then reconnect Server B i want it to be standby and to stay Server A Main._**

**_Is this possible to Setup? I also tried the "lose Arbitration" Option, but i cannot force my wanted Situation._**

**_Thanks and best regards_**

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AFarooq:
Currently there is no way to default set a server to be Main. The arbritation is done internally with set rules that are not available to the user to control. I was told by support that there are plans to add the ability for users to decide which ones of the paired servers should become primary after a main-main or main-standby switch. Dont expect the solution soon as I can imagine the Dev team will have to figure out how to handle the switch for customers with large databases. You cant just switch them on the fly due to synchronization issues.

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bevanweiss:
Umm.. well there are some ways to achieve what AFarooq is talking about

Altering the Arbitration Priority such that Server B has a higher Arbitration Priority to Server A. Then in a Main-Main scenario, Server B will always win the Arbitration.
This obviously doesn't work in a straight failure/shutdown scenario however.. Generally logic is used to force a particular server to be Main in such a situation.

For your scenario, it's almost like you want the arbitration to be reversed.
The way ClearSCADA does it is it considers the winning server to be the one that has been running for the longest period of time. It sounds like you want the most recently promoted server to continue running as main.

I haven't heard of this before. Is there a reason you want this?

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AWoodland:
Isolated Main and isolated Standby, with suitable ICMP monitoring could well achieve what they're after, i.e ensuring the Main server with the most visibility of things stays Main.

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**_FeWo:_**
**_Yes, that was my mistake, i had to configure the ICMP Monitors. Now its working. Thanks!_**