There is often confusion around what the available configurations are for EMC Avamar. I can attest to this because I deal with it on a daily basis and I usually get confused……it could be the rum but let’s not speculate at this point. 
When you start looking at Avamar for your environment you will undoubtedly hear terms like “Single Node”, “RAIN”, “Grid”, “Utility Node”, “Gen2 Node”, “Gen3 Node”, “Deep Node” and “Shallow Node”. Now unless you’re an EMC engineer or have really done a deep dive into the Avamar technology you’re probably going, “What does all this crap mean?”. Well let me see if I can simplify it a little.
First let’s dumb down the terminology to where normal people can understand them:
- Single Node:
- A single stand-alone node of Avamar with the brains and the storage capacity all in one.
- RAIN Configuration:
- Redundant Array of Independent Nodes. Think of a RAID5 array of servers instead of disks
- Storage Node:
- A single Avamar server appliance (2U server). They are available in 1TB, 2TB and now 3.3TB configurations.
- Utility Node:
- An Avamar appliance similar to the storage node (same physical size) that works as the brains of an Avamar system.
- Deep Node:
- Typically this was a 2TB Storage node. Now that the 3.3TB nodes are out I guess those will be REALLY Deep Nodes….but who knows.
- Shallow Node:
Now let’s look at the different types of Avamar solutions that are available:
The Single Node
The single node Avamar solution is just what it sounds like, 1 Node (appliance) that backs up your data. This node contains but the Avamar software “Brains” and the disks necessary to store the data. This solution is available in 1TB, 2TB or 3.3TB sizes. This is the most basic Avamar configuration and is good for small shops or remote locations that may require fast recovery of data. The downside to this configuration is that it is limited from a scalability standpoint. Once you fill it up you have to either add another single node and manage it separately or buy multiple nodes and upgrade it to a “Grid” or “RAIN” configuration which I’ll discuss later. Another big drawback is that you have to replicate the solution (buy 2 single nodes). This is to protect from node failure which would result in data loss. Both nodes can be sitting in the same datacenter side by side but they must be replicated.
The Grid
Avamar can be configured in a “1×2 Grid” architecture. This includes 2 single nodes and 1 utility node to do all the work. The benefit of this configuration is purely space. If you need more than 3.3TB of Avamar this would be one way to accomplish that. The downside of this configuration is the same as the single node in that it also must be replicated to guard against node failure.
The RAIN Configuration
Ah ha, finally, a configuration that doesn’t have to be replicated. The RAIN configuration is built using a minimum of 4 storage nodes and 1 utility node. Again think of this as RAID5 with physical servers instead of just disks. There are 2 common initial configurations for this RAIN architecture. One is called a DS510, DS520 or DS530 and the other is called a DS610, DS620 or DS630. The 500 series consist of 5 nodes and the 600 series consist of 6 nodes – genius huh! The last two numbers (10, 20 or 30) represent the size of the storage node. A DS510 would have five 1TB nodes, a DS520 would have five 2TB nodes and so on. Let’s take a look at the DS520 and DS620 architectures which seem to be the most common.
- DS520
- 3 Active 2TB Storage Nodes
- 1 Spare 2TB Storage Node
- 1 Utility Node
- Up to 6TB licensable capacity
- DS620
- 4 Active 2TB Storage Nodes
- 1 Spare 2TB Storage Node
- 1 Utility Node
- Up to 8TB licensable capacity
There are several benefits of going with a RAIN architecture. First, you don’t have to replicate the solution although if you are trying to protect yourself from a complete datacenter disaster you may want to replicate to a DR site. Everything is internally redundant in a RAIN configuration. The second and probably biggest advantage to RAIN is scalability. If you max out your configuration simply add another node to the array and you’re off to the races.
A quick note about the different “GENs” of Avamar:
Avamar is currently in its 3rd generation which basically means the hardware platform has changed. Avamar nodes are based on a DELL R710 server, before that it was a Dell 2950 server. As the server hardware changes so will the GEN usually. Avamar is backward compatible so if you have a GEN2 RAIN configuration you can add GEN3 nodes to it without any problems. The only catch is that you cannot add 3.3TB nodes to a RAIN configuration that is built on 2TB nodes.
Hopefully that simplified things a little, if not please feel free to send hate mail. Happy holidays!
