MDM - Master\Slave doubts

[Former Member]

Hi!

I am writing you because I have some MDM MasterSlave doubts, can you please help me?

As far as I know MDM is not supported under MSCS (Microsoft Cluster) and the development recomendation is to use the MasterSlave mechanism...

Is it possible to create a slave repository in a different server from where the master repository exists? For instance Master repository is in host A and Slave repository is in host B. According to http://help.sap.com/saphelp_mdm550/helpdata/en/42/f006c39e671bc9e10000000a11466f/content.htm it appears that it is possible. If I understand:

1. right-click on the MDM repository for which you want to create a slave and choose Create Slave

2. Select the RDBMS server

So in 2. it seems that it can be a remote RDBMS server, can you confirm?

The other doubt is if there isn't any virtual hostname or virtual IP assigned to the master repository and if this host fails how will the applications be redirected to the slave repository? I am asking this because customer wants to achieve high-availability and MSCS is not supported for MDM, only MasterSlave configuration.

Many thanks in advance!

Best regards,

Raú

[Former Member · Accepted solution]

Hi!

I think that Raul's doubt is not answered at all...

Regarding the first question, if slave repository can be on another host, it is answered.

But the second one, if the master repository host fails, how can slave assume the operations?

If the MDM configuration in (for instance) SRM is pointing to Master Repository host how can it be redirected for the Slave Repository host? Is there a second MDM configuration that can be done in SRM in case the first one fails (just like SCM Optimizer)?

If there is a restriction (like Simona told) that both the master and slave repository need to be on the same server, this server become a Single Point of Failure...

So, how can we avoid Single Point of Failures in MDM?

Thanks!

Best regards!

Pedro

[former_member278106]

Hi Raul,

MDM slave repository may be normalized even when it is loaded by using CLIX in less than a second, but active clients will need to login to new MDM server to continue working. Automatically it may be done by using load balancer. At present MDM doesn't have built-in load balancer, but you may use for this purpose third-party tools. You may find more "MDM High availability" related information in the "MDM 5.5 SP05 - Solution Operation Guide" in the section "High availability" on page 33. The document may be found on the SAP Marketplace on:

http://service.sap.com/~sapidb/011000358700000316992007E

Best regards,

Lev

[Former Member]

Raul,

Slave is a read only repository.

in the Fail over you can connect to the slave just for Display ONLY.

To use the salve you have to stop the repository Normalize and load the repository.

Starting mds is fast loading the repository will take longer time based on number of records.

You should use the backup's are the slave by doing the above steps.

Thanks,

madhu

[Former Member]

Hi Krutarth,

Thanks for your reply but it is not what I was asking for.

That procedures doesn't eliminate Single Point of Failures.

Best regards,

Pedro

[Former Member]

Hi,

In case of Host failure you can re-gain the repository by following ways:

<b>MDM Archive and Unarchive</b>

You can use the MDM Console Archive command to create a DBMS independent backup of the MDM repository that completely encapsulates the repository. The archive file can be copied to offline storage for safekeeping, and used to later restore the repository using the Unarchive command, either on the same DBMS machine or a different DBMS machine.

<b>MDM Duplicate.</b>

You can use the MDM Console Duplicate command to simply create a copy of the MDM repository in case the original is corrupted. The repository can be duplicated to a different drive on the same DBMS machine or onto a different DBMS machine

<b>Native DBMS backup and restore</b>.

You can, of course, always use the native backup and restore methods provided with your DBMS by invoking the DBMS commands directly. This requires knowing the names of the actual databases (or schemas), as discussed in Duplicating an MDM Repository

However,In addition to backing up each of the repository partitions, you must also back up the single MDM database/schema that maintains information on all the MDM repositories.

More infomation can be availed by visiting <a href="http://help.sap.com/saphelp_mdm550/helpdata/en/42/f05ee776b41bc7e10000000a11466f/frameset.htm">this URL</a>

Regards,

Krutarth

[Former Member]

Hi Colleagues,

First of all thanks for your replies. Now I'm able to understand my first question

I agree with Pedro, that I need, replies for the second question: if the master repository host fails, how can slave assume the operations? how can we avoid Single Point of Failures in MDM?

Please could you help me?

Thanks and regards

[Former Member]

Hello Raul,

Are you asking about the details of redirecting requests to the right MDM Server or whether a slave repository can replace its master?

A slave repository can serve any read-only request the same way its master can. Some implementations actually direct all read requests to slave(s) so as to reduce load on the master. If you want to redirect write operations, the slave will need to be Normalized. Once that is done, the ex-slave can be made a Master.

In order to redirect requests on a failover, a redirector application will need to be created.

For a single-repository MDM installation, there are two points of failure: the MDM server where a repository is mounted and the DBMS server where the repository is stored. The DBMS can be replicated using its own replication methods. Replicating MDM Servers is somewhat more complex.

Hope this helps,

Simon

[Former Member]

Hi Rahul,

As answered earlier the slave repository can be created on a different server -confirmed.

As for your question on if the master host fails at any time how to carry on ?

- There is a provision in MDM where by you can make a slave repository act as a master repository.

- So must synchronize your slave to the master regularly and at any point if you realize you master host can fail you can make this updated slave repository as your master repository and continue with the process.

- For this there is a DBMS restriction that both the master and slave repository need to be on the same server,however i am not very sure of this restriction.

- But this method can work.

Hope it helped

Regards

Simona

[Former Member]

Hello Simona,

> - For this there is a DBMS restriction that both the

> master and slave repository need to be on the same

> server,however i am not very sure of this

> restriction.

> - But this method can work.

There is no such "DBMS restriction." When a slave repository is deployed on the target MDM Server, there is no need for it to share the master repository's DBMS instance, type or anything else.

Hope this helps,

Simon

[Former Member]

Hello Raul,

Yes, mdm is not clusterable (MSCS).

When you ask about creating a slave repository a different server, do you mean a DBMS server? If you do, then yes, a slave can be created on any DBMS instance the MDS can connect to. If the master's MDS cannot connect to the desired DBMS instance, you can always create the slave on any convenient DBMS instance, archive it, and unarchive onto the desired DBMS instance on the right MDM server.

Yes, the RDBMS server can be as remote as it can be.

Redirection of incoming requests to a slave on failover does not happen automatically within the core MDM. You might want to check with your SAP consultant about setting that up.

Hope that helps,

Simon

Hi!

I am writing you because I have some MDM MasterSlave

doubts, can you please help me?

As far as I know MDM is not supported under MSCS

(Microsoft Cluster) and the development recomendation

is to use the MasterSlave mechanism...

Is it possible to create a slave repository in a

different server from where the master repository

exists? For instance Master repository is in host A

and Slave repository is in host B. According to

http://help.sap.com/saphelp_mdm550/helpdata/en/42/f006

c39e671bc9e10000000a11466f/content.htm it appears

that it is possible. If I understand:

1. right-click on the MDM repository for which you

want to create a slave and choose Create Slave

2. Select the RDBMS server

So in 2. it seems that it can be a remote RDBMS

server, can you confirm?

The other doubt is if there isn't any virtual

hostname or virtual IP assigned to the master

repository and if this host fails how will the

applications be redirected to the slave repository? I

am asking this because customer wants to achieve

high-availability and MSCS is not supported for MDM,

only MasterSlave configuration.

Many thanks in advance!

Best regards,

Raú