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Does anyone have experience to share about High Availability AF Collective

XCATA

Does anyone have experience to share about High Availability AF Collective

 

Specifically with the below setup in mind:

1) using Network Load balancing for two AF Servers.

2) using AlwaysOn for the AF SQL servers(running in a Windows Server Failover Cluster).

 

All comments are welcome!!

 

 

 

 

In the PI Live Library it is stated that using the Network Load balancing method for AF is "Not recommended with asset analytics, event frames, and notifications"

- Why is this not recommended? Due to difficulty in setting it up or due to instabillity?

 

PI AF-based high-availability solutions

The following table shows a comparison of  PI AF-based high-availability solutions.   PI AF-based solution  Advantages  Disadvantages  Clustered  No real advantages, other than it can help restart the service if it fails. 
  • Requires significant initial investment in cluster hardware.  
  • PI AF server unavailable during cluster failover period.  
  • No real advantage over having single server service restart itself on failure.  
Network Load Balancing (NLB)  Allows for load balancing across multiple servers using NLB clusters or round-robin DNS.  Network Load Balancing can be single point of failure if unavailable.    PI AF collective (with static load balancing)  Low-cost entry into high availability. 
  • Static load balancing across  PI AF collective members requires per-client  PI AF SDK configuration.  
  • As of today, no dynamic load balancing is available.  
Note: Not recommended with asset analytics, event frames, and notifications.

 

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  • 0

    Hi Carsten,

     

    Can you copy/paste the PI Live Library link here? To my knowledge there are no issues between Notifications/Analysis and an NLB AF Server. Are you sure the comment "Not recommended with asset analytics, event frames, and notifications" was not tied to the AF Collective ?

     

    Note that for AF HA, there are the SQL back end HA considerations as well as the AF Server HA considerations. This KB article is very good at summarizing your options:

     

    https://techsupport.osisoft.com/Troubleshooting/KB/KB00634

     

    In this KB there is the comment "Not recommended with asset analytics, event frames, and notifications", which is applicable to the SQL Transactional replication a SQL HA consideration that is used with AF Collective. This is in no way tied to having an NLB configured.

     

    Hope this helps,

    Sebastien

  • 0 in reply to Community User

    Correct I mixed it up.

    If you look at the table I copy/pasted into this thread, it has that comment in the row describing the PI AF Collective.

    PI Server

    Thank you for the link to the KB article it actually shows what is recommended by OSI Soft. It was not clear in the article in the Live Library.

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