running and stores all your assets: metadata about where to find your assets, where assets can be data, users and groups, etc. It is a centralized resource for storing, managing, and also providing metadata for all your SAS applications, for all your users.
In-memory: when your users request data, a copy of the physical data is stored into memory. From there on, your users are going “against” memory. This speeds up the process so that the access time is quicker. Memory is flushed when you pause and resume, or, stop and restart the metadata server.
When speaking about metadata assets, we are referring to libraries, users, groups, SAS folders – everything you create using SAS Management Console or SAS® 9.4 Open Metadata
Interface (metadata server programming language). SAS applications also create and manage metadata.
To learn more about the SAS 9.4 Open Metadata Interface, take a look at https://go.documentation.sas.com/api/docsets/omaref/9.4/content/omaref.pdf
These assets are stored in a metadata repository. A repository is like a box in which you save all your belongings. Your main repository is Foundation. You can also create custom and project repositories. When SAS is installed, only one repository is created, which is the Foundation one.
A custom repository can be used – as one example – in cases where you might have very sensitive data that should only be available to a certain group of users. The custom repository and its contents could be created in a directory where only these users have access to.
Project repositories are used for Change Management and are available for SAS Data Integration Studio only. Users can check out and lock metadata so that metadata can be modified and tested, to be checked back in afterward, which then unlocks the metadata.
In this book, we will focus on the Foundation repository. To learn more about custom and project repositories, check out About Repositories at https://go.documentation.sas.com/?cdcId=bicdc&cdcVersion=9.4&docsetId=bisag&docsetTarget=p1b7gxgkbu04zbn1dhnh3pb8c6zs.htm&locale=en
When you log on to SAS Management Console, Foundation is chosen per default as shown in Figure 2.4.
Figure 2.4: SAS Management Console
| Note: The path defaults to SAS-conf-dir/Lev1/SASMeta/MetadataServer/MetadataRepositories/. Do not rename or delete the metadata server repository path and never move, delete, or modify data sets in the MetadataRepositories and rposmgr directories. |
You can remove metadata objects via SAS Management Console or by using metadata programming features using the SAS® 9.4 Open Metadata Interface. Before you delete or remove any metadata objects, I recommend the following information from the sasCommunity.org Planet: “Where is my stuff? Documenting what is stored in SAS Metadata” available at: http://www.sascommunity.org/planet/blog/category/metadata/. Note: if you are using the printed book version, I realize that having to type a link into a web browser is a bit laborious, but this is one of the articles that are really helpful, and hard to find if you don’t dig deep. Typing it is worth it.
Metadata server and system access
You can use the metadata server’s authorization model to control access to your SAS assets (aka metadata objects). SAS security does not include protection of configuration files or any non-SAS-related content. In the Appendix of the book, you will find an overview of the operating system protections for Windows and Unix/Linux. Chapter 6, SAS 9.4 Metadata Security will cover metadata server authorization.
How about a clustered metadata server? Let’s talk high availability!
You have the option to set up the SAS Metadata Server as a clustered configuration. A metadata server cluster provides redundancy and high availability, which helps you make sure your environment will continue to operate should one metadata server go down.
You can implement metadata server clustering at any time. It does not have to be set up during the initial install.
A common question is if the SAS clients know when one cluster node goes down and another one picks up. There is no configuration for your SAS clients necessary. SAS clients, such as SAS Management Console, keep a list of the metadata server cluster nodes, which is updated each time a client connects to the cluster.
Where changes are required is for the SAS Application Server tier. Application servers such as the Object Spawner, workspace server, stored process server, etc. don’t understand that there is a cluster all of a sudden. Application servers use a configuration file – called metadataConfig.xml – which tells them about the metadata server. So as long as you don’t make changes to this file, the SAS application servers still assume that there is only one metadata server. The SAS middle tier applications keep a list that is automatically updated when the Web Infrastructure Platform web application starts. This is all described in the information for metadata server clustering, which you will find in the resource references in the Appendix of this chapter.
In addition to the official SAS documentation about metadata server clustering, you will find some other great resources such as papers and blogs.
How do clients interact with the metadata server?
When users start a SAS client, such as SAS Enterprise Guide, a connection profile is used to connect to the metadata server. I will talk about Connection Profiles a little later in this chapter.
Metadata Server logging
The default location for the Metadata Server log file is:
SAS-config-dir\\Lev1\SASMeta\MetadataServer\Logs
SAS 9.4 uses a standard logging facility to perform logging for the metadata server and all other SAS servers. Generally, the default logging information are sufficient, as it provides you with information, warnings and errors. SAS Technical Support might ask you to increase the logging level if more precise information is needed for troubleshooting. You can certainly modify the logging levels at any time. Just keep in mind that increasing the information the metadata server writes to the log, the metadata server log file size will grow. Maintaining log files will be discussed further in the housekeeping chapter.
Note: If the reason for considering enabling additional logging is because you want more information for auditing and monitoring, logging will not fulfill your needs. In Chapter 3, SAS Administration Tools, we will talk about SAS Environment Manager, which provides you with some great options for monitoring or auditing.
Important: If you look at the individual log folders for your SAS servers, you will notice that the workspace server does not have any log files. A workspace server log is written for each individual user. Let your users work for a day with a workspace server log enabled and you’ll end up with an abundance of log files. Workspace server logs are usually only enabled when SAS Technical Support needs information for further troubleshooting. Enabling workspace server logging just out of curiosity can affect the performance.
About the Workspace Server, Stored Process Server and all other SAS Servers
These servers are called SAS Application Servers. The
