[THIN] Re: Dual ZDCs?

We are not using bonding.  The NICs are used for different traffic - one NIC for client traffic coming from WI and one NIC for back-end traffic to run backups, send/receive files from our interface server etc.

 

We have a dedicated server for our SQL server data store.

 

I finally figured out disparity between member servers not rendering users, sessions, shadowing etc.  It boils down to networking.  For servers in different subnets we only open ports 2512, 2513 and 1494 from member servers to our 2 ZM named servers (used for primary and backup ZDC).  Once I presented my findings to our System Architects and Engineer, they agreed this was the case and the reason behind my original question.  I guess I won't forget this now that I spent 3 days wondering about it.

 

Thanks,

 

Stephanie Atkinson

Joe Shonk <joe.shonk@gmail.com> wrote:

Do these servers have multi-nics connected to different networks?  If so,  that is probably where your problem lies…  While it is possible to use multiple NICS (not bonded), it is highly NOT recommended and definitely not a best practice.

 

Each zone had a 1 Data Collector (DC) that is elected.  So if you have two zones, you will have two DCs (or we like to call them ZDCs).

Any server that has direct access to the database can function as a DC so in order to dedicate a server/vm to this role you must set the election preference (Most Preferred).  Some organizations like to have a backup ZDC.  Technically, there is no such thing.  It's simply a server that has been dedicated to serve as the ZDC in the event the real ZDC become unavailable.  Again, this is accomplished by setting election preference so the machine is next in line.  This prevents an application server from becoming the DC in the event of a failure.

 

Now having a "backup" ZDC is nice because you can also use that server to host additional infrastructure services or act as a backup.  So in the event of a failure of an infrastructure server you're not impacting your application servers.  Examples of additional infrastructure services.   DC Role, XML, STA, Metric Server.  Smaller farm could also host Web Interface and the Licensing server (CTX and/or MS) while large orgs will want to split WI and Licensing onto separate servers.

 

Also, the imalhc.mdb is the local host cache,  not the Data Store.  Do you know if your data store is Access, SQL Express or SQL?

 

Joe

 

From: thin-bounce@freelists.org [mailto:thin-bounce@freelists.org] On Behalf Of Stephanie Atkinson
Sent: Thursday, December 04, 2008 5:49 AM
To: thin@freelists.org
Subject: [THIN] Re: Dual ZDCs?

 

Hi Jeremy,

Thanks for your suggestions.  I checked out a few things yesterday after speaking with a more senior Admin who has been on vacation.  In some ways he confused me even more trying to tell me that when you build the farm you designate the zone masters (2 in our case supposedly, when to me it just seems like a primary of most preferred and a backup of preferred) and that that info is stored in the imalhc.mdb (copy of persistent, not non-persistent data) on each server telling it to only communicate with the ZM in that database.  He also explained how the member server communicates with the ZM via the MGT NIC then the ZM sends the info back on the client-side NIC thus it's only able to send back to the same member server.  I find flaws with both of these explanations but I think you're right that the answer to my question lies in our configuration.  One thing I did find is that we don't have ports 2512, 2513 or 1494 open between non ZM servers, only from member server to ZM.  That would seem to account more for the lack of available info in the CMs.

I started questioning this b/c I am studying for my CCA.  The more you learn the more you can question.  Anyhow, I will just keep digging into this.  Thanks for your clarifications.

Best Regards,

Stephanie

Jeremy Saunders <Jeremy.Saunders@datacom.com.au> wrote:

Hi Stephanie,

 

Have a look at the way the Presentation Server Administrators have been set up in the Access Management Console, and perhaps also the DCOM permissions on the servers, ensuring that the COM Plus network access Windows component has been added to all servers. As far as I'm concerned, this stuff should configured the same across all servers. Maybe you need to quiz that Engineer a bit further???

 

Cheers,

Jeremy.

 

From: thin-bounce@freelists.org [mailto:thin-bounce@freelists.org] On Behalf Of Stephanie Atkinson
Sent: Wednesday, December 03, 2008 8:23 PM
To: thin@freelists.org
Subject: [THIN] Re: Dual ZDCs?

 

I'd forgotten the qfarm identifies the ZM as well.  I ran that and it confirmed just 1 ZM is in affect.  So then here is where I guess I am confused.  You stated,

By the way, it is not a requirement to run the Access Management Console or Presentation Server Console (AKA CMC) from the Data Collector. Any farm server will do, and if your zone is working correctly, the information returned will be consistent no matter which server you connect to.

and when I read that ports 2512 and 2513 are used for server to server and server to MC respectively, I took that to mean that all MCs from all servers in a given farm provide results for all servers in the farm. In our case, it is only the dedicated primary and backup ZMs that have this bird's eye view for Servers.  The MCs from any other server DO provide Pub App and Policies data for example but NOT Servers.  So you can't see what users are logged on, try to shadow or directly connect to any other server than the one you are logged on to. 

Regards,

Stephanie



Jeremy Saunders <Jeremy.Saunders@datacom.com.au> wrote:

Hi Stephanie,

 

What you are seeing is correct, it obviously just hasn't been explained to you correctly. The Engineer should have whiteboarded this for you.

 

Each zone can only have ONE Data Collector at any one time. You have a "Primary", which will always be the server set to "Most Preferred", and you have a Backup, which is set to "Preferred". The backup will take over when the Primary fails, is taken off-line, etc. I personally always set the remainder of farm member servers to "Not Preferred" to ensure they never take part in any zone elections. Others will leave them set to "Default", just in case.

 

If you go to the command line on any server, type "qfarm". This will list all servers in the farm. The ones with the D after their IP Address will be the active Data Collectors for those zones. So in your case you will see two.

 

By the way, it is not a requirement to run the Access Management Console or Presentation Server Console (AKA CMC) from the Data Collector. Any farm server will do, and if your zone is working correctly, the information returned will be consistent no matter which server you connect to.

 

I hope that explains it.

 

Cheers,

Jeremy.

 

From: thin-bounce@freelists.org [mailto:thin-bounce@freelists.org] On Behalf Of Stephanie Atkinson
Sent: Wednesday, December 03, 2008 9:58 AM
To: thin@freelists.org
Subject: [THIN] Dual ZDCs?

 

How is it that a Zone can have 2 operating Data Collectors?  Of everything I have read, each zone can only have one so maybe I misunderstand what is going on.  The Citrix Engineer who setup this environment advised we have data collection on 2 servers because 1 is set to Most Preferred and the other Preferred.  All other servers are left to default. We have 2 dedicated servers for each zone intended to be data collectors and by all accounts that is how they are working.  All the information from every server in the zone is available from both servers in the CMC; all other servers only provide their local information.

 

Can anyone clarify or explain this?

 

Thanks,

 

Stephanie Atkinson

 

  

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