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HIS Server centralisation question RRS feed

  • Question

  • Background: My customer has over 1000 branches and each branch has a HIS Server on its own subdomain. These servers are in 3 different windows domain. All the HIS configurations are about the same except the server name, PU name, LU name and talking to a CICS region in the same HOST mainframe. We want to combine the servers into fewer HIS servers without changing the application.

    I beleive the application is using the workstation ID name as the local APPC LU alias. The local APPC LU alias are W01-W99 with majority of workstations in the lower range. And each APPC Alias is associated with a dependent LU.

    I am thinking of a centralised HIS server farm with the following:

    A maximum of 15 HIS Servers per subdomain. I read somewhere the maximum per subdomain is 15. Is this correct ? Configure 2-3 servers with the same CICS region with 6 to choose from. This would give a balancing effect on the mainframe as well.

    1 of the server is Primary with the rest as Backup and each server can serve as a sponsor server.

    Since there are 3 windows domains, I could create 3 HIS server farms, one for each domain. I could use one farm since the 3 domains are trusted but I am worried 15 servers may not be able to serve the requests in time if the same workstation id in each branch is using the application. If I choose 3 farms, then a maximum of 45 servers may be required.

    The workstations has HIS Client installed and configured with the 15 servers, use update list dynamically and select random sponsor to create load balancing effect between the servers. I found the HIS Client Whte paper quite useful in this regard. The problem I have is when there are more than 15 requests from the same workstation in different branches, the 16 request may not be able to find a free APPC dependent LU to use.

    Assuming the requests are Ad hoc and not frequent and the same workstation id from different branches do not use the application simultaneously.

    Could the above solution work ?

    Saturday, November 24, 2012 11:59 AM

Answers

  • This should work. I can't recall anyone that I have worked with that has used the "default pool" for dependent APPC LUs because normally when you see these used there are tie-ins between the LU and a user/workstation. In these cases, the design is such that there was a desire for an LU to be used by a specific device or user.

    Thanks...


    Stephen Jackson - MSFT

    Friday, December 7, 2012 3:00 PM

All replies

  • Peter,

    There is a limit of 15 HIS Servers per HIS subdomain. However, each HIS Server can run four SNA Server services (nodes). If there was a concern about hitting any limits based on SNA Server service (node) limits, then using multiple SNA Server service per HIS Server gets around some of those limits.

    You didn't indicate how many APPC LUs are defined across all of the HIS Servers that are currently in use, but you may be able to use one subdomain of HIS Servers to handle the load. Typical APPC transactions are not very resource intensive and usually send/receive small amounts of data.

    From the description, it should like you are using Dependent APPC LUs, which makes it a little more configuration intensive since you may need to define one Local APPC LU per end user workstation based on your description above. Independent APPC LUs are better in most cases because they support parallel sessions which means you can use many fewer APPC LUs in the environment.   

    Each connection in HIS can support up to 255 dependent LUs (per IBM limits on dependent LUs per PU definition). This means that you can handle a large number of LUs on each server. A HIS Server can support up to 60,000 sessions.

    If you'd want each client to have fault tolerance, you could do so using the same APPC LU Alias on multiple servers. If each client can only access one Local APPC LU, then you'd have to use Active/On Demand connections because the same dependent LU cannot be activated more than once. For example, a client would have a "primary" connection that is uses normally. If that connection or server were down, there would be another "backup" connection configured for an On Demand startup that could be used if the "primary" connection is unavailable.

    Thanks...


    Stephen Jackson - MSFT

    Tuesday, December 4, 2012 4:30 PM
  • Stephen,

    Currently it is using 99 APPC LU with majority of them only using the first 20. I beleive the application is calling the APPC LU Alias W01 to W99 instead of the actual LU name. Although this is a little more configuration intensive, at least it is easy to troubleshoot the issue when it arises. It must be hard to troubleshoot if it is using a pooling method.

    I don't know why this application is using dependent APPC LU instead of Independent LU. Not sure if there was some sort of restriction on the mainframe CICS system or the age of the application. Newer applications which use independent LU has moved on except this one. Changing from dependent LU to independent LU may involve changing the application which is not desirable.

    I was reading the following artilce:

    http://allcomputers.us/windows_server/biztalk-2009---host-integration-server-2009---sna-load-balancing.aspx

    Can I use the "default outgoing Local APPC LU pool" described in this article for dependent LU ?

    Not sure if the application can work with pooling and not sure what changes are required in the application. It would be nice if the application do not use the APPC LU alias and can use the next available APPC LU similar to a pooling method.

    I have also read the following article

    http://support.microsoft.com/kb/128244

    It mentioned the Local APPC LU alias must not be specified by the APPC application in its TP_STARTED request. Without knowing the application, this indicates a change of application may be required.

    Peter

    Wednesday, December 5, 2012 12:33 PM
  • The "default outgoing local APPC LU pool" is not used in cases where the APPC application specifies a Local APPC LU alias.

    If the Local APPC Lu alias is defined on multiple HIS Servers (Local APPC LUs define on different HIS Server with unique LU Names, but the same LU Alias), you can still take advantage of load balancing/fault tolerance even if the APPC application specifies the Local APPC LU alias. HIS Server load balances on the Remote APPC LU. If the Remote APPC LU is defined on multiple HIS Servers, then the APPC application can get a session via any of these HIS Servers assuming the Local APPC LU alias is also defined on those HIS Servers.

    Thanks...


    Stephen Jackson - MSFT

    Thursday, December 6, 2012 5:06 PM
  • Stephen,

    I was thinking if the application changes to not specify a Local APPC LU alias, can we change the local APPC LU alias to be the same as LU name. I want to create a pooling effect with "default outgoing local APPC LU pool" so that any LU could be used to process incoming transaction. I assume support would be difficult since there is no fixed LU to process the transaction based on the workstation name if there is probnlem. Do you think it will work ?

    Peter

    Friday, December 7, 2012 4:48 AM
  • This should work. I can't recall anyone that I have worked with that has used the "default pool" for dependent APPC LUs because normally when you see these used there are tie-ins between the LU and a user/workstation. In these cases, the design is such that there was a desire for an LU to be used by a specific device or user.

    Thanks...


    Stephen Jackson - MSFT

    Friday, December 7, 2012 3:00 PM