EMC E20-598 Backup Recovery - Avamar Specialist Exam for Storage Administrators Exam Practice Test

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For initial backup of Avamar clients, it's best to start with a small number of clients to produce a dataset fromwhich commonality will be generated. This will increase the backup speed of following clients. On a newAvamar system, consider enabling overtime because all the data is new and there won't be much maintenanceto take place. Never enable overtime on an existing Avamar, rather configure the use of partial backups to besaved. Partial backups are saved for 7 days and are not deleted by the garbage collection process. When anunfinished job ends before completing and partial backups are enabled, the backup job will continue from thelast known state and will complete faster.

http://gregandthenetwork.blogspot.com/2013/12/avamar-configuration-design-best.html

https://communities.vmware.com/message/2166196

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During the backup window, an Avamar server has 18 backup "slots" per node, minus one slot that is globallyreserved for restore.

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Avamar Node Types and Processes

There are several different types of Nodes within an Avamar Server. The Utility node is the identity of theAvamar Server and provides the bulk of the internal Avamar server processes such as: Avamar Administrator(used to manage the Avamar Server from a gui), cron jobs, DNS, NTP, external authentication, web access,MCS and EMS.

MCS (Management Console Server) provides centralized management including scheduling of backups,restore of backups, monitoring and reporting.

EMS (Enterprise Manager Server) provides web based management for multiple Avamar Servers as well asmonitoring and configuration for Avamar Replication.

Web Access provides access to documentation, backup plug-ins as well as remote File System restoreaccess to end users.

Are next type of node is the Storage Node, which run a process called gsan. This service communicates withthe avtar command on the individual backup clients. Avtar communicates with a storage nodes gsan process,then that storage node spreads the data across the available data nodes.

A Spare Node is an active node that is present in a multi-node RAIN (Redundant Array of Independent Nodes)grid. The interesting thing about the Spare Node is that it is NOT a hotspare. There is a procedure in placethat needs to be followed when a failed Storage Node occurs. In fact, the Avamar Server doesn’t even care ifthe Spare Node is powered on, so if you are a “Green” conscience company, feel free to leave the Spare Nodepowered down. EMC Best Practice is to leave the Spare Node up and active though.Avamar Backups clients can be installed with 2 different types of client plug-ins: File System and Databases.The Avamar client uses 2 processes in the backup and restore process: Avtar and Avagent. The Avagentprocess listens for backup/restore work orders from the MCS service on the Utility Node using port 28002 andexecutes the avtar command that handles the backup/restore processes and communicates with the gsanservice on the storage nodes. This process is depicted in the included picture above.Lastly, in a previous blog, I discussed the 2 different licensable options for Avamar and how the disks arecomprised in each Storage Nodes type. These are depicted in the picture above as well as a breakdown ofhow the disks are structured.

Please stop back by later, I plan to talk about the NDMP Accelerator and it’s role in the Avamar System.

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The most important thing to do on a client with so many files is to make sure that the file cache is sizedappropriately. The file cache is responsible for the vast majority (>90%) of the performance of the Avamarclient. If there's a file cache miss, the client has to go and thrash your disk for a while chunking up a file thatmay already be on the server.

So how to tune the file cache size?

The file cache starts at 22MB in size and doubles in size each time it grows. Each file on a client will use 44bytes of space in the file cache (two SHA-1 hashes consuming 20 bytes each and 4 bytes of metadata). For 25million files, the client will generate just over 1GB of cache data.

http://jslabonte.blogspot.com/2013/08/avamar-and-large-dataset-with-multiples.html

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Single Node.

Also known as the Non-RAIN (Redundant Array of Independent Nodes) configuration. This is the entry levelconfiguration in which the single node acts as the utility node and the data storage node. When using thisconfiguration 2 single nodes are needed. 1 is the main backup node, andthe 2nd is used for replicationpurposes for fault tolerance. Used in small to medium sized environments.

Muti-Node Non RAIN.

This is basically is a 3 node setup consisting of 1 Utility Node and 2 Data Storage Nodes. It allows for doublethe storage capacity of a Single Node device.

This configuration also needs a duplicate setup for replication, so a total of 6 Nodes would be needed for faulttolerance. Used in medium sized environments.

Multi-Node RAIN.

The Standard RAIN configuration has 1 Utility Node, 4 Data Storage Nodes and 1 Spare Node. This

configuration can be expanded for a total of 16 Data Storage Nodes max. All of the nodes work together tobalance the storage equally across all of the other Data Storage Nodes. This architecture is easily scaled byadding as many Storage nodes as necessary. Typically used in large environments, this configuration can beinitially setup with 3 Storage nodes instead of the standard 4 Storage nodes. It is recommended to setup aduplicate Multi-Node RAIN for replication, typically at a DR site. Although it is recommended, it is not anecessity like the Non-RAIN configurations, because there is a spare node that can be configured at any pointfor fault tolerance.

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While performing the backup of system state using Windows VSS plugin choose the option "Create DisasterRecovery Backup", this option will allow you to perform restore of the system using "Avamar disaster RecoveryWizard"

https://community.emc.com/thread/114519

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http://whughgriffin.wordpress.com/2011/07/05/avamar-ads-gen4-node-hardware/

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vamar, has a rather nifty technology called Sticky Byte Factoring which allows it to identify the changedinformation inside a file by breaking the file into variable length objects, this leads to much greater efficiencythan fixed size approaches as changes made early in a fixed length sequence affect all subsequent blocks/chunks/objects/whatever in that sequence. This in turn changes all the fingerprints taken following the changeddata which means you end up with a lot of new blocks/chunks/objects/whatever even if the data really hasn'tchanged all that much. Sticky Byte Factoring on the other hand can tell what exactly has changed, not just thatthings have changed.

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