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Question about connection manager feature

  • 1.  Question about connection manager feature

    Posted 3 days ago
    Hello All, 

    I have a question about the connection manager feature.
    Is it possible to failover to a cold standby server using informix connection manager instead of using cluster software like pacemaker or PowerHA?

    ------------------------------
    SangGyu Jeong
    Software Engineer
    Infrasoft
    Korea, Republic of
    ------------------------------


  • 2.  RE: Question about connection manager feature

    Posted 3 days ago
    Hi SangGyu,

    define 'cold standby'.

    CM, roughly, would only even consider any secondary it a) already is connected to, so it b) can judge its synchronicity with the primary, i.e. only live Informix cluster members.
    If you're thinking of the same instance, brought up on same disks, only on a different host, that's none of CM's business.

    Andreas

    ------------------------------
    Andreas Legner
    ------------------------------



  • 3.  RE: Question about connection manager feature

    Posted 3 days ago
    @AndreasLegner
    Thanks for the kind answer.
    I wanted to know if I could use the connection manager to replace other cluster software.
    The standby server must be operated in the form of a secondary server. ​

    ------------------------------
    SangGyu Jeong
    Software Engineer
    Infrasoft
    Korea, Republic of
    ------------------------------



  • 4.  RE: Question about connection manager feature

    Posted 2 days ago

    Andreas:

    "If you're thinking of the same instance, brought up on same disks, only on a different host, that's none of CM's business."

    Well, unless you've configured it as an SDS....






  • 5.  RE: Question about connection manager feature

    Posted 3 days ago
    SangGyu:

    Failover to a "cold server" as in one that is not online until needed? No, not in the way you mean - to start up the cold server. The failover server has to be an HDR, RSS, SDS, or ER node that is actively online. That raises the question of why would one not take advantage of HDR for such a secondary give that there is no license cost and the hardware is already there? Why wait several minutes until an offline server can be brought online which will take several minutes for a Continuous Log Restore secondary which might be one or more logs behind the primary, or worse, several hours while a completely offline server is restored from an archive and rolled forward when you can have an HDR secondary online at near instantaneous speed with only a handful of transactions rolled back?

    There is one way to point users to a cold backup server. That would be to use a GROUP in the sqlhosts file as INFORIXSERVER and have that group include the connection details for both the primary and the secondary. Connection Manager can do that also, it just cannot start up the offline server.

    Art

    ------------------------------
    Art S. Kagel, President and Principal Consultant
    ASK Database Management Corp.
    www.askdbmgt.com
    ------------------------------



  • 6.  RE: Question about connection manager feature

    Posted 3 days ago
    @Art Kagel
    Thank you for your reply.
    Most of the customers I've met have used powerHA or other cluster software only to configure Informix high availability features.
    Perhaps customers are more familiar with configuring using cluster software than unfamiliar programs such as informix connection manager.
    (Customers may want uniformity in software configuration because they have to manage various DBMSs together.)
    Of course, few customers use Informix, which consists of a connection manager and SDS server, but most customers tend to configure high-availability features with minimal cost.
    So I wanted to know if connection manager was possible instead of cluster software.

    I think the method using the warm standby configuration of SDS server and connection manager is the most cost effective.
    Anyway, We plan to use pacemaker for cold standby configuration. :)


    ------------------------------
    SangGyu Jeong
    Software Engineer
    Infrasoft
    Korea, Republic of
    ------------------------------



  • 7.  RE: Question about connection manager feature

    Posted 3 days ago

    @SangGyu

    HDR is sooo much simpler to set up and manage, more reactive (a few seconds) for failover, more accurate (HDR deals about transactions, Power HA deals with computers)  and way cheaper than Power HA

    That I would not think twice before giving preference to HDR

     

     

     

    Eric Vercelletto
    Data Management Architect and Owner / Begooden IT Consulting
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  • 8.  RE: Question about connection manager feature

    Posted 3 days ago
    @SangGyu

    Assuming this is the HA environment of old then you can just start informix on the other server and you should be good. But via CM I don't think so, AFAIK CM can not run a script when a failure is detected.

    It can be automated within the cluster though and CM should reconnect to new server (with a little care)

    Cheers
    Paul

    Paul Watson
    Oninit LLC
    +1-913-387-7529
    www.oninit.com
    Oninit®️ is a registered trademark of Oninit LLC





  • 9.  RE: Question about connection manager feature

    Posted 3 days ago
    @Paul Watson
    Hello Paul,
    It was concluded that the cluster software could be replaced by configuring the secondary server and CM together. ;)
    Of course, when using CM, I think there will be limitations on functions such as disk or process monitoring and heartbeat check.​

    ------------------------------
    SangGyu Jeong
    Software Engineer
    Infrasoft
    Korea, Republic of
    ------------------------------



  • 10.  RE: Question about connection manager feature

    Posted 3 days ago
    Definitely can if you have a hot standby server. Back in the day it cost you to have a hot standby so the HA env would control the failover

    Cheers
    Paul

    Paul Watson
    Oninit LLC
    +1-913-387-7529
    www.oninit.com
    Oninit®️ is a registered trademark of Oninit LLC





  • 11.  RE: Question about connection manager feature

    Posted 3 days ago
    @Eric Vercelletto​​
    Hello Eric,
    I think HDR is good too, but I like that it takes twice as much storage when configured, and that it takes a long time to rebuild an instance due to an unexpected split-brain. In addition, we have experienced several problems with poor transaction processing performance due to unsophisticated in-house applications, so we have not been able to easily recommend HDR configurations to our customers.

    ------------------------------
    SangGyu Jeong
    Software Engineer
    Infrasoft
    Korea, Republic of
    ------------------------------



  • 12.  RE: Question about connection manager feature

    Posted 3 days ago
    Use ER - that might negate some of the app layer issues 

    Cheers
    Paul

    Paul Watson
    Oninit LLC
    +1-913-387-7529
    www.oninit.com
    Oninit®️ is a registered trademark of Oninit LLC





  • 13.  RE: Question about connection manager feature

    Posted 3 days ago

    SangGyu:

    Connection Manager failover requires all servers in the cluster to be on-line and in sync with the primary. So you can fail over to a warm standby, but not a cold one.






  • 14.  RE: Question about connection manager feature

    Posted 3 days ago
    @TOM GIRSCH​​​
    Thanks for checking again.

    ------------------------------
    SangGyu Jeong
    Software Engineer
    Infrasoft
    Korea, Republic of
    ------------------------------