Going Green with Virtualization Part 2: Storage Virtualization

Wednesday, May 13th, 2009

In part 1, I discussed how to leverage Virtual Tape to green the datacenter and the environment. In this part, I will focus on how storage virtualization can help reduce power consumption and datacenter floor space requirements.

Let’s start with a typical high availability datacenter using Monolithic storage. Those big ol storage arrays are massive, can really suck up power,  and put out a LOT of heat.

10TB monolithic Array

Weight Weight Heat      Power

(kg)        (lb)         BTU        (kVA)

 810         1,781    18036     5.5

Now let’s compare that with a modular array with the same amount of storage:

10TB modular Array

Weight Weight Heat      Power

(kg)        (lb)         BTU        (kVA)

 130         287        119          1.31

Now, why do people buy the big monolithic arrays? 2 reasons: Reliability and capability.

What does all this have to do with storage virtualization? Simple. By virtualizing the storage with an intelligent virtualization platform which can provide all the data services required at the fabric level, you remove the need for intelligence in the storage array (capability), thereby making it a commodity. You can then use the virtualization platform to mirror data between modular arrays and even replicate data offsite to improve data availability (reliability)

Modular vs Monolithic

The Monolithic array takes up 4 to 6 floor tiles in the datacenter, outputs over 18000 BTU, and consumes 5.5 KVA of power. If the array goes down, you declare a disaster.

The 2 Modular arrays take up 2 floor tiles in the datacenter, output only 238 BTU, and consumes 2.62 KVA of power. If an array fails, nothing happens, and the applications stay live.

Although this may seem simplistic and unfair to the advantages of intelligent monolithic storage, If those services can be accomplished more efficiently and cost effectively (Optimized)  by using storage virtualization, then  so be it. The green advantages become obvious, since the savings shown can be doubled based on not requiring another monolithic array at the DR location.  Monolithic arrays may make sense when they provide services for many servers, and the servers can take advantages of the global cache in the array. In those cases, storage virtualization can simply be used to provide replication services to modular storage at the DR site, so at least the DR site can be greener.

In the next part, I will discuss the obvious advantages of data deduplication in greening the datacenter.

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