SCCM System Discovery

* Active directory system discovery in SCCM is used to discover devices in active directory Domain service.

* To run the System discovery go to Administration pane.
* Expand Overview-> Hierarchy configuration->Discovery methods-> Active directory system discovery
* Once you select it right click and run "Full Discovery Now" option.

SCCM client log and troubleshooting for patching

* SCCM is a beast in itself. It's client has so many components that even if 1 Component is not working,it can cause issues
* Log files are the heart of troubleshooting for SCCM.You have to know which log file to read in which order for effective troubleshooting
* All SCCM log files are in location C:\Windowds\ccm\logs folder
* For patching issues follow the following order for troubleshooting.
*First step is to see whether patches are getting download to the client. The patches once downloaded are stored in ccmcache folder.
*This folder is in C:\windows\ccmcache
*If patches are not downloaded  in this folder then you have problem with client not able to download the patches from WSUS server.
*  You should immediately look for log called wuahandler.log
*Look for errors in this log most likely you will see error connecting to WSUS server.
* Generally the easiest troubleshooting step I do if I see this error only on few clients is to uninstall and reinstall the client from the
* Mostly this should resolve if there is client issue. . I suggest doing the install from SCCM console and choose the location for the source to I still from site location.

SCCM key services

SCCM has some key services

SMS Executive service
SMS agent host service
SMS Component service
SMS VSS writer service
SMS backup service

What are the various Site System Role in System center configuration manager (SCCM) Current Branch

Service connection point:

• A site system role that uploads usage data from your site, and is required to make updates for Configuration Manager available in the console. This role also helps to manage mobile devices with Microsoft Intune and on-premises MDM. 

• A hierarchy only supports a single instance of this role, and that must be at the top-tier site of your hierarchy. If you expand a standalone primary site into a larger hierarchy, uninstall this role from the primary site, and then install it at the central administration site. 

Reporting services point:

• A site system role that integrates with SQL Server Reporting Services to create and manage reports for Configuration Manager. 
• This role is supported at primary sites and the central administration site, and you can install multiple instances of this role at a supported site.

Software update point:

• A site system role that integrates with Windows Server Update Services (WSUS) to provide software updates to Configuration Manager clients. This role is supported at all sites:

State migration point:

• When you migrate a computer to a new operating system, this site system role stores user state data. This role is supported at primary sites and at secondary sites. Install multiple instances of this role at a site, and at multiple sites in the same hierarchy.

Management point:

• A site system role that provides policy and service location information to clients. It also receives configuration data from clients.
• By default, this role installs on the site server when you install a new primary or secondary site. Primary sites support multiple instances of this role. 

Fallback status point:

• A site system role that helps you monitor client installation. It identifies clients that are unmanaged because they can't communicate with their management point. 

Enrollment proxy point:

• A site system role that manages Configuration Manager enrollment requests from mobile devices and macOS computers. Although this role is supported only at primary sites, you can install multiple instances of this role at a site, or at multiple sites in the same hierarchy.

Enrollment point:

• A site system role that uses PKI certificates for Configuration Manager to enroll mobile devices and macOS computers. Although this role is supported only at primary sites, you can install multiple instances of this role at a site, or at multiple sites in the same hierarchy.

Distribution point:

• A site system role that contains source files for clients to download, for example:

Application content
Software packages
Software updates
OS images
Boot image

Asset Intelligence synchronization point:

• A site system role that connects to Microsoft to download information for the Asset Intelligence catalog. This role also uploads uncategorized titles, so that Microsoft can consider them for future inclusion in the catalog.

Data warehouse service point:

• Use the data warehouse service point to store and report on long-term historical data in your Configuration Manager environment.

Cloud management gateway connection point:

• A site system role for communicating with the cloud management gateway.

Certificate registration point:

• A site system role that communicates with a server that runs the Network Device Enrollment Service (NDES). This role manages device certificate requests that use the Simple Certificate Enrollment Protocol (SCEP). This role is supported only at primary sites and the central administration site.

Application Catalog website point:

• A site system role that provides users with a list of available software from the Application Catalog. Although this role is supported only at primary sites, you can install multiple instances of this role at a site,

Application Catalog web service point:

• A site system role that provides software information to the Application Catalog website from the software library. Although this role is supported only at primary sites, you can install multiple instances of this role at a site, or at multiple sites in the same hierarchy.

SMS Provider:

• The assigns this role to each computer that hosts an instance of the SMS Provider. The provider is the interface between a Configuration Manager console and the site database. By default, this role automatically installs on the site server of a central administration site and primary sites. Install additional instances at each site to provide access to additional administrative users or for redundancy.

Configuration Manager site database server:

• The site assigns this role to site system servers that hold an instance of the site database. Only move this role to a new server by running setup to modify the site to use a different instance of SQL Server to host the site database.

SCOM Agent performance counter showing dotted lines in graph

Many might have face this issue.

The only solution is to uninstall the SCOM agent ,reboot the server. Recreate the wmi repository, then install the SCOM Agne to resolve the issue.

Features of Apache Cassandra

* Elastic scalability - Cassandra is highly scalable; it allows to add more hardware to accommodate more customers and more data as per requirement.

* Always on architecture - Cassandra has no single point of failure and it is continuously available for business-critical applications that cannot afford a failure.

* Fast linear-scale performance - Cassandra is linearly scalable, i.e., it increases your throughput as you increase the number of nodes in the cluster. Therefore it maintains a quick response time.

* Flexible data storage - Cassandra accommodates all possible data formats including: structured, semi-structured, and unstructured. It can dynamically accommodate changes to your data structures according to your need.

* Easy data distribution - Cassandra provides the flexibility to distribute data where you need by replicating data across multiple data centers.

* Transaction support - Cassandra supports properties like Atomicity, Consistency, Isolation, and Durability (ACID).

* Fast writes - Cassandra was designed to run on cheap commodity hardware. It performs blazingly fast writes and can store hundreds of terabytes of data, without sacrificing the read efficiency.

Advantages of Apache Cassandra

* It is scalable, fault-tolerant, and consistent.

* It is a column-oriented database.

* Its distribution design is based on Amazon’s Dynamo and its data model on Google’s Bigtable.

* Created at Facebook, it differs sharply from relational database management systems.

* Cassandra implements a Dynamo-style replication model with no single point of failure, but adds a more powerful “column family” data model.

* Cassandra is being used by some of the biggest companies such as Facebook, Twitter, Cisco, Rackspace, ebay, Twitter, Netflix, and more.