• Abhishek Shukla

Dell EMC Avamar

A few days ago, I discussed about the data protection solutions and explained about Dell EMC's integrated solution called IDPA, its architecture and deployment techniques. IDPA is abbrevation of Integrated Data Protection Appliance. It includes several other components i.e. Dell EMC Avamar as backup solution and many more. I thought of exchanging some information about Avamar in this article.


As per the definition at the data sheet of Dell EMC Avamar , it is defined as :

"Dell EMC Avamar enables fast, efficient backup and recovery through its integrated variable-length deduplication technology. Avamar is optimized for fast, daily full backups of physical and virtual environments, NAS servers, enterprise applications, remote offices and desktops/laptops.

Avamar is available as a virtual edition or as a component of Dell EMC Data Protection Suite, which offers you a complete suite of data protection software options."


Before I proceed with Avamar's introduction, I would explain a little about Data Deduplication with Avamar.


Deduplication is the technique referred to eliminating duplicate copies of repeating data to improve storage utilization. In this technique, the data is divided into small chunks. These chunks are analysed and stored. The chunks are then compared to the stored copy of the data and whenever a match occurs, the redundant chunk is replaced with a small reference that points to the stored chunk.

Data Deduplication is the key feature of Avamar. Data deduplication ensures that each unique small data, variable length object is stored only once. At the time of backups, Avamar client software examines the client file system and applies a data deduplication algorithm which identifies same data sequences and breaks the client file system into sub file, variable length data segments. Each data segment is assigned a unique ID. The client software then determines whether this unique ID has already been stored on the Avamar server. If this object resides on the Avamar server, a link to the stored object is referenced in the backup. Once an object has been stored on the server, it is not sent over the network again, no matter how many times it is encountered on any number of clients. This feature significantly reduces network traffic and provides for greatly enhanced storage efficiency on the server.


Introduction to Avamar:

The Avamar is a network based backup and restore solution by Dell EMC. It works on a client/server model. The bunch of Avamar servers make a Avamar System. The system consists of one or more Avamar servers and the network servers and desktop clients that backup data to those servers.


Avamar System is built up of Avamar Server and the Nodes. Each node consists of self contained, rack-mountable, network addressable compute that runs Avamar server software on the linux OS. Bunch of nodes on a rack will be creating a Avamar Server. Basically, node is a building block in any Avamar Server. Let me elaborate more individually.


Avamar Server:

Avamar is a hard disk based IP network backup and restore solution. Avamar servers use internal hard disk storage. One Avamar server is nothing but a logical grouping of one or more nodes. Avamar ensures fault tolerance by managing disk drive space in units of space called stripes. In the Avamar system, an object is a single instance of deduplicated data. Each Avamar object inherently has a unique ID. Objects are stored and managed within stripes on the Avamar server.


Avamar Nodes

As I mentioned in the earlier section, the node is the primary block in any Avamar Server. Nodes contains internal storage in the form of hard disk drives If the node is configured with internal storiage i.e. single node server, it is internally mirrored to provide fault tolerance feature.

Nodes are defined in three different types :

  1. Storage Node: These nodes store backup data. Multiple storage nodes are configured with multi-node Avamar servers which are based on performance and capacity requirements.

  2. Utility Node: The utility node is dedicated to scheduling and managing background jobs. In scalable multi-node servers, a single utility node provides essential internal services for the server i.e.

  3. Management console server (MCS)

  4. External Authentication

  5. Network Time protocol (NTP)

  6. Web access

  7. NDMP accelerator: This one is a special node which uses NDMP to provide data protection for NAS devices.


Architecture of Avamar Server

There are three main components which build the architecture of Avamar. These are


1. Data Server: While performing a backup, restore, or validation, Avamar backup clients communicate directly with the data server. All scheduled backups are initiated by the MCS scheduler.


2. Management Console Server (MCS): The MCS provides centralized administration (scheduling, monitoring, and management) for the Avamar server. The MCS also runs the server-side processes that are used by the Avamar Administrator graphical management console.

MCS functions

a. Client Registry: Controls client registration and activation.

b. Account management: Used to create and manage domains, clients, users, and groups

c. Reporting: Used to create and export system reports

d. Events: Displays system events and activities.

e. Scheduler/dispatcher: Controls when backup and restore operations occur, or if the operations can be queued for processing.

f. PostgreSQL DB: Stores Avamar server data. PostgreSQL is an open architecture database management system. Information in the MCS database is accessible through any PostgreSQL-compliant ODBC interface. The MCS database file name is mcdb, and it is on the utility node in the /usr/local/avamar/var/mc/server_data/ postgres directory. The MCS database contents are fully backed up on the Avamar server and can be restored when the MCS fails.


3. EM Tomcat Server (EMT): The Avamar EM Tomcat server (EMT) provides essential services that are required to display, and work with Avamar server information. The EMT also communicates directly with MCS. This communication is a required part of all Avamar systems.



Avamar Clients

Avamar provides client software for various computing platforms. Each client comprises a client agent and one or more plug-ins.



Agents:

Avamar agents are platform-specific software processes that run on the client and communicate with the Management Console Server (MCS) and any plug-ins that are installed on that client.


Plug-ins:

There are two types of Avamar plug-ins:

• File system plug-ins that are used to browse, back up, and restore files or directories on a specific client file system.

• Application plug-ins that support backup and restore of databases or other special applications.



With this information, I will end up this article of introduction of Avamar. I will write one "How-to" article with the deployment details and configuration in my next article. Thanks for reading. Hope this was an informative for you.

"An investment in knowledge
always pays the best interest"
                      -             
Benjamin Franklin

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