Cloud storage is generally broken out into two broad classifications: public storage clouds and private storage clouds. But as cloud storage technologies continue to mature, it is quickly becoming evident that these two categorizations are insufficient. Recent offerings from providers like 3PAR, EMC and IBM demonstrate that a new cloud storage tier is emerging. This tier extends the benefits of cloud storage up the application stack so that data center applications can also take advantage of the cloud storage architecture.
The concept of cloud storage is resonating with all size organizations for a number of reasons but possibly the biggest is that it makes managing data much easier. By creating a single logical pool that stores and manages data, the effort associated with routine, ongoing maintenance tasks such as data migrations, system upgrades, and even determining on which storage device to store the data is markedly reduced or even goes away.
However most cloud storage (public or private) solutions are designed the way they are for one simple reason: they are designed to host archival, backup and infrequently accessed data. Since 80% or more of an organization’s data fall into one or all of these three categories, current cloud storage solutions primarily seek to deliver acceptable performance, high capacity and low cost. To do this, first generation cloud storage offerings use inexpensive servers, storage and network interfaces to meet these demands.
These requirements change as you go up a notch and start to apply cloud storage architectures to data center environments. Data center managers also want to harness the benefits of cloud storage (simplified data migrations, system upgrades and a single logical pool of storage) but need other characteristics that typical cloud storage solutions do not provide. New characteristics that define a data center cloud storage offering include:
- Block based interfaces. While some private storage cloud offerings offer iSCSI as a block based interface, this protocol is generally viewed as insufficient for performance intensive applications. So any cloud based offering that is to be used by a data center will need to support protocols such as Fibre Channel (FC) or FC over Ethernet (FCoE) to satisfy its performance demands.
- Multiple tiers of storage. First generation cloud storage offerings primarily use SATA drives to store data because they are high capacity and low cost. The downside is that these drives are relatively low performing. While data center managers certainly desire to store some of their inactive production data on this tier of storage, they also have a percentage of their application data that requires higher performing FC, SAS and even new SSD. So whatever cloud storage solution they deploy has to support all of these tiers of storage capacity.
- Dynamic placement of application data on the appropriate tier of disk at the right time. Just having multiple tiers of storage capacity is not enough. There must be intelligence added into the storage system that automatically places data on the appropriate tier of storage according to the application’s needs. This placement needs to be policy driven, done automatically and adjust dynamically to changing application requirements.
- Simplified storage provisioning in block-based environments. This is one of largest hurdles that this emerging data center cloud storage tier has to overcome. The need for this feature is driven by server virtualization where a single physical server may host multiple virtual machines each with its own unique identifier. When this host is connected to a storage cloud, performing tasks such as zoning on FC switches and directors and applying LUN masking to each LUN become numerous and complex. While it can be done manually, it becomes very time consuming and risky as it introduces the potential for human error. To avoid this, the data center tier must provide a means to simplify and automate this very cumbersome and time consuming process.
- Risk-averse. This may sound like an oxymoron in the data center world – how can you implement a cloud storage solution and minimize risk while doing so? However that is exactly what is required in order for these managers to feel comfortable adopting a data center cloud storage solution.
The new problem that results from this data center tier of cloud storage is that in addition to only one logical pool of data being created, it also creates a storage system that functions logically as one entity. This means tasks that are currently segregated (firmware updates, zoning and LUN masking changes, etc. because they are on physically different storage systems) are now consolidated onto one unit.
This gives rise to the potential that a single mistake or even a series of unrelated mistakes can bring down the entire storage cloud – an unacceptable proposition in data centers. So in order for a cloud storage solution to achieve the “Data Center Tier” classification, it must provide checks and balances such that data center managers have the flexibility and ability to control what changes are implemented, when they are implemented and under what circumstances.
The concept of cloud storage has infused new enthusiasm into a part of the technology industry that is historically perceived as a bit more conservative. But even now that conservative nature is on full display as cloud storage starts to move up the application stack into enterprise data centers. Notice that it is not unknown providers that are looking to deliver a data center tier of cloud storage but recognizable names and emerging brands within these established storage providers such as the 3PAR InServ Storage Server, the EMC V-Max, and the IBM XIV.
This is where data center managers need to be on their guard. As this new “Data Center Tier” of cloud storage continues to mature, each provider is developing its own set of options to solve these aforementioned challenges. As they do, what will separate the best products from the also-rans are those that provide the right underlying framework (hardware and software) that make this new data center tier of cloud storage affordable to obtain, easy to implement and manage, and does so without putting their enterprise at risk.